Routine Coronary Arteriography Research Articles

Another cause of chest pain: Coronary artery—Pulmonary artery fistulae

This report describes three patients with coronary artery fistula from proximal left anterior descending artery to the pulmonary artery. Retrospective analysis of 2756 adults undergoing coronary arteriography for evaluation of angina pectoris between July 1988 and January 2000 revealed coronary artery fistulae in three patients: one male (46 years old) and two females (45 and 53 years old). No murmur was audible in any patient. There was no associated significant coronary artery disease. The feeder arteries to the fistulae for all three patients were left anterior descending coronary artery. One of the patients underwent cardiopulmonary bypass and the fistulae was ligated, due to very strong angina. The diagnosis is mostly incidental during routine coronary arteriography. We concluded that the coronary artery-pulmonary artery fistula might be a cause of angina without audible murmur and may sometimes need surgical ligation.

La ausencia de manifestaciones clínicas que sugieran isquemia coronaria pretrasplante renal es suficiente para predecir la ausencia de eventos coronarios postrasplante

The association between kidney disease and coronary disease is well established, so special care must be taken in the cardiological assessment carried out before being added to the renal transplant waiting list. The performing of a routine coronary arteriography has also been proposed. Objective To analyse whether the clinical assessment is sufficient to predict the absence of post-transplant coronary events. Patients and method A total of 256 current dialysis patients were examined in Cardiology. An electrocardiogram, echo doppler and a clinical assessment were performed on all the patients. Other examinations were not performed if the clinical signs were not suggestive of ischaemia. Post-transplant coronary events were analysed on those who had received a renal graft. Results There were 94 (36.7%) patients on the kidney transplant waiting list. Age: 50.12 ± 13.8 years; 57 (60.6%) men; 13 (13.8%) diabetics. Only one patient (1.06%) showed coronary disease at the time of being added to the waiting list. The coronary arteriography on the first assessment or during the monitoring was performed on 3 patients (3.2%) and two of them showed coronary disease. As result of an acute coronary syndrome, a patient died while on the waiting list. Fifty-two (55%) patients were transplanted after 29.3 ± 13.3 months on the waiting list (median: 35). After the transplant, they were followed up for 22.1 (16.5) months (median: 20), without any cardiological events. Conclusions 1. The pre-inclusion of cardiological clinical assessment on the renal transplant list was sufficient to predict the absence of post-transplant coronary complications. 2. Additional procedures were not necessary when there are no clinical signs that suggest the presence of coronary ischaemia.

WE-C-304A-04: In Vivo Analysis of Coronary Blood Flow and Arterial Tree Volume Relationship in Swine

Purpose: To investigate in vivo the scaling laws relating regional blood flow and lumen volume in the coronary tree using angiographic image data. The correlation between regional blood flow and the distal lumen volume can potentially be used to assess stenosis severity during routine coronary arteriography. Method and Materials: Coronary arteriograms were acquired at maximal hyperemia induced by intracoronary injection of papaverine (5–10mg) in a swine animal model (25–35 kg, N=3). All images were acquired using a conventional x‐ray tube with a constant potential x‐ray generator (Optimus M200, Philips MedicalSystems) and a cesium iodide based flat panel detector (PaxScan 4030A; Varian Medical Inc.). The flat panel detector has a 40×30 cm2 field of view and pixel size of 0.194×0.194 mm2. Contrast material was power injected at 4 ml/sec. A calibration phantom was imaged over the heart region for system iodine calibration. The coronary arterial tree was divided into approximately 6 subtrees down to stem diameters of less than 1 mm. Regional blood flow and lumen volume measurements were made using previously validated techniques. Results: Regional blood flow (Q) and lumen volume (V) were related by Q = 154.67V3/4 (R=0.991). The standard error of estimate for the regression was 8.04 ml/min or 14.65%. Conclusion: Normal hyperemic blood flow can be estimated using the distal lumen volume of the coronary arterial tree. This makes it possible to quantify fractional flow reserve, which is used to assess stenosis severity during routine coronary arteriography.

Predictive value of coronary artery stenoses and C-reactive protein levels in patients with stable coronary artery disease

Introduction and aims Coronary occlusions resulting in acute events often occur at the site of non-severe stenoses. We sought to assess the prognostic value of non-obstructive coronary stenoses and C-reactive protein (CRP) levels in patients with chronic stable angina (CSA). Methods We studied 790 consecutive patients with CSA who underwent routine coronary arteriography. High sensitivity CRP and coronary angiograms were assessed at study entry. Angiographic coronary disease severity was graded using a “vessel score” (number of coronary arteries showing at least 50% reduction in lumen diameter) and extent of disease with an “extension score” (proportion of the coronary artery tree showing angiographically detectable atheroma). Patients were followed up for 1 year. Results Significant left main stem disease was present in 54 patients (6.8%). 368 patients (46.6%) underwent revascularization. 71 patients (9%) had at least one of the events comprised in the combined study end-point (unstable angina, myocardial infarction (AMI) and cardiac death). Patients who suffered cardiac adverse events had a significantly higher vessel score ( n) (2.0 [2.0–3.0] vs. 2.0 [1.0–2.0], P < 0.001), extension score (%) (23.5 [17–34.5] vs. 16.0 [6.0–27.0], P < 0.001) and CRP levels (mg/L) (3.0 [1.8–7.2] vs. 2.3 [1.1–4.7], P = 0.001) compared to patients without events. Age, previous history of AMI, vessel score, extension score and CRP levels were significantly associated with the study end-point. Multivariate analysis showed extension score (OR 5.3 [2.8–10.3] CI 95%; P < 0.001), revascularization (OR 0.26 [0.14–0.48] CI 95%; P < 0.001) and CRP levels (OR 1.9 [1.1–3.2] CI 95%; P = 0.03), but not vessel score ( P = 0.1), to be independent predictors of the combined end-point. Conclusions In patients with CSA, independently of revascularization, extension score and CRP levels predict cardiac adverse events, regardless of the presence or absence of flow limiting coronary lesions.

TH-C-I-611-04: Experimental Validation of An Angiographic Method for Determining Coronary Fractional Flow Reserve

Purpose: To investigate an angiographic technique for determining fractional flow reserve (FFR) for assessing anatomic and physiologic significance of intermediate coronary stenoses from routine coronary arteriography. Method and Materials: A swine animal model was used to investigate an angiographic method for determining FFR for different severity stenoses. The proximal portion of the left anterior descending (LAD) artery was dissected free from the epicardium. An ultrasonic transit-time flow probe was implanted distal to the left main coronary artery bifurcation. A vascular occluder was positioned distal to the flow probe to apply different levels of stenoses. Acquired angiograms were corrected for scatter-veiling glare and pincushion distortion. Coronary arterial flow and lumen volume were determined angiographically from a first-pass distribution analysis. A computer simulation utilizing a fully reconstructed swine coronary arterial system was used to study the coronary arterial flow-volume relation. Results from this simulation study were used to determine hypothetical normal flows from measured arterial lumen volumes. Angiographic FFR was calculated from the ratio of the measured hyperemic flow to the hypothetic normal flow derived from the arterial lumen volume and compared to FFR measured directly with the flow probe. Results: Simulation studies showed that coronary flow (Q) was related to cumulative lumen volume (V) through a power-law relation. For vessels detectable by coronary angiography (>0.1 cm3), a linear relationship was observed between coronary flow and lumen volume (Q= 5.2+45V; R=0.992). Experimental validation of this flow-volume relation showed similar results (Q= −0.503+52.4V, R=0.997). A comparison between FFR measured with angiography and with the flow probe showed good correlation (r>0.9). Conclusion: Regional coronary flow can be determined with angiography, and normal regional flow without the presence of stenosis can be calculated using flow normalized to arterial lumen volume. Thus FFR can be calculated from the same images obtained from routine coronary arteriography.

Regional volumetric coronary blood flow measurement by digital angiography: In vivo validation 1

Rationale and objectives There are well-known limitations to the use of visual estimation to assess the severity of coronary artery disease and luminal stenosis. This is especially true in the case of an intermediate coronary lesion (30%–70% diameter stenosis), where coronary arteriography is very limited in distinguishing ischemia-producing intermediate coronary lesions from non-ischemia-producing ones. For this reason, a functional measure of stenosis severity is desirable. The goal of this study is to validate a video densitometry technique for quantitative assessment of regional volumetric coronary blood flow. Materials and methods Coronary arteriography was performed in eight swine (body weight, 25–50 kg) after power injection of contrast material into the left main coronary artery. Phase-matched subtracted images were used to quantify regional coronary blood flow using a video densitometry technique. The in vivo regional flow measurements were validated using a transit time ultrasound flow probe. Results In 44 measurements, the ultrasound (Q US) and video densitometry (Q VD) regional flow measurements were related by Q VD = 0.98 Q US + 0.11 mL/min ( r = 0.98). The results of mean regional coronary blood flow measurements for repeated coronary arteriograms of the first (Q VD1) and second (Q VD2) measured flows were related by Q VD1 = 1.04 Q VD2 + 0.05 mL/min ( r = 0.97). Conclusions A video densitometry technique for quantification of regional coronary blood flow was validated using a swine animal model. The results demonstrated the feasibility and potential utility of the video densitometry technique for accurate measurement of regional coronary blood flow, in vivo. This study provides an angiographic method that can potentially be used to evaluate intermediate coronary lesions during routine coronary arteriography.

Coronary and Carotid Artery Disease in Patients with Degenerative Aneurysm of the Descending Thoracic or Thoracoabdominal Aorta: Prevalence and Impact on Operative Mortality

From January 1, 1995 to July 31, 2000, a total of 133 patients underwent elective surgical treatment for degenerative aneurysm of the descending thoracic (n = 45) or thoracoabdominal (n = 88) aorta. There were 116 men (87%) and 17 women (13%) with a mean age of 66.4 +/- 8.7 years (range, 39 to 84 years). Sixteen patients (12%) died in the immediate postoperative period. Thirteen patients (10%) had already undergone myocardial revascularizaton. Thirty-five patients (26%) presented clinical symptoms of coronary artery disease. Preoperative coronary arteriography was performed in 84 (63%) patients, demonstrating normal findings or clinically insignificant lesions in 48 patients (57%), single-vessel lesions (>70% reduction in diameter) in 19 patients, two-vessel lesions in 12 patients, and three-vessel lesions in 5 patients. On the basis of these findings, myocardial revascularization was performed before aortic repair in 11 patients. The total number of myocardial revascularization procedures in this series was 24 (18%). Four patients had previously undergone a total of 6 carotid endarterectomy procedures. Routine duplex ultrasound demonstrated significant carotid artery lesions in 12 patients (9%). Ten of these patients (8%) underwent carotid endarterectomy. The total number of carotid endarterectomy procedures in this series was 16 in 14 patients. The prevalence of coronary and carotid lesions in patients indicated for elective treatment for degenerative aneurysm of the descending thoracic or thoracoabdominal aorta was similar to that observed in patients presenting degenerative aneurysm of the infrarenal abdominal aorta. Univariate analysis demonstrated that coronary and carotid lesions with or without treatment are a significant risk factor for mortality following surgical repair of degenerative aneurysm of the descending thoracic or thoracoabdominal aorta. This finding suggests that routine preoperative coronary arteriography and duplex ultrasound are warranted.

Quantification of coronary artery lumen volume by digital angiography: in vivo validation.

Coronary artery lumen volume may potentially have several advantages over the commonly used variables, such as percent stenosis or minimal lumen diameter, in the assessment of coronary artery disease. The goal of this study is to validate a quantitative assessment of lumen volume using a video densitometry technique. Coronary arteriography was performed in 9 swine (body weight 20 to 55 kg) after power injection of contrast material (2 mL/s for 3 seconds) into the left main coronary artery. Phase-matched subtracted images were used to quantify regional lumen volume by a video densitometry technique. The in vivo volume measurements were validated by a polymer cast of the coronary arterial tree made at physiological pressure. The measured cast volume (V(C)) and video densitometric regional lumen volume (V(VD)) were related by V(VD)=1.06 V(C)-0.01 mL (r=0.99). The root mean square and systematic errors for these measurements were 17% and -3%, respectively. A video densitometry technique for quantification of coronary lumen volume was validated both in vitro and in vivo in a swine animal model. The present results demonstrated the feasibility and potential utility of the video densitometry technique for accurate measurement of regional lumen volume in vivo. This study contributes to the understanding of the angiographic methods used for the assessment of coronary artery disease and indicates that this technique can potentially be used for quantification of diffuse coronary artery disease during routine coronary arteriography.

Stent in acute non-Q wave myocardial infarction

Dear Editor, This is in reference to the case report “Stents in non-Q wave myocardial infarction” along with very informative discussion by Lt Col JS Duggal et al. Some important aspects though need to be highlighted. 1. Patients presenting with non-Q wave Myocardial Infarction (NQWMI) have a long term outcome, which is similar to that with a Q wave MI (QWMI), including the subset of patients who undergo coronary revascularisation (Fig 1). Thus, there has been extensive use of coronary arteriography (CAG) and revascularisation following NQWMI in an attempt to reduce subsequent morbidity and mortality. Fig. 1 The outcome alter angioplasty for recurrent ischemia after a Q wave or non-Q wave myocardial infarction is similar. Angioplasty was performed because of recurrent ischemia after a Q wave myocardial infarction (175 patients) or a non-Q wave infarction ... 2. Patients with mechanical complications, recurrent angina, electrical instability or congestive heart failure following NQWMI, have a very high risk of reinfarction and death. As a result, CAG followed by revascularisation is used extensively in these patients with complicated NQWMI. In uncomplicated NQWMI cases, routine CAG followed by PTCA of the culprit lesion performed days to weeks after acute NQWMI has become a standard practice at many centres. Only one trial, VANQWISH trial [1], which compared early and late coronary interventions in patients with NQWMI only, reveals that there is no evidence of benefit from an early invasive strategy in patients with uncomplicated NQWMI (Fig 2). Patients who do not have left ventricular (LV) dysfunction or inducible ischemia are at low risk of recurrent events and may well be harmed by unnecessary invasive procedures (Fig 3). Fig. 2 Conservative therapy is better after NQWMI Kaplan-Meier analysis demonstrates that, for patients with a non-Q wave myocardial infarction (NQWMI), a conservative strategy (catheterization and revascularization only for evidence of ischemia) results in ... Fig. 3 A conservatice management approach is effective for a non-Q wave myocardial infarction. Two studies have compared a conservative approach (medical therapy with catheterization and reascularization when clinically indicated) with an invasive approach (catheterization ... 3. Thus recommended approach to CAG and revascularization in patients of NQWMI based on those published by the ACC/AHA task force on practice guidelines (committee on coronary arteriography) [2] is as follows: Patients with cardiogenic shock should undergo immediate coronary angiography followed by PTCA or CABG if anatomy is suitable. Patients with mechanical complications, recurrent angina, electrical instability or CHF following NQWMI should also undergo prompt CAG followed by PTCA or CABG based upon anatomical considerations. Patients with uncomplicated NQWMI should have a non-invasive assessment of LV function and a physiologic evaluation for ischemia prior to discharge. Those with significant LV dysfunction or evidence of inducible ischemia should undergo CAG followed by revascularisation based upon anatomic considerations. There is no apparent benefit from an early invasive approach. The remaining patients are at low risk for recurrent events and should be treated medically. 4. As per recent ACC/AHA guidelines for treatment of patients with NQWMI, Diltiazem is recommended in patients only if there is no LV dysfunction or pulmonary congestion [2]. Also, short-term therapy with ACE inhibitors appears to be beneficial in NQWMI patients with anterior infarction and long-term treatment appears to be effective in those with reduced LV function [3]. 5. Stents in acute MI have come a long way. A large number of case reports and small series support a potential role for intra-coronary stents for acute Ml with success rate reported from 81 to 98%. Although primary stenting improves the short-term outcome of patients, long-term data are sparse. The American College of Cardiology experts consensus documents state that stenting is a promising approach to optimize the results of primary angioplasty for acute Ml and to treat complications [4]. Whether stenting should be used only to treat sub-optimal results or should be recommended as a primary therapy, is still uncertain.

Another cause of chest pain: Coronary artery—Pulmonary artery fistulae

This report describes three patients with coronary artery fistula from proximal left anterior descending artery to the pulmonary artery. Retrospective analysis of 2756 adults undergoing coronary arteriography for evaluation of angina pectoris between July 1988 and January 2000 revealed coronary artery fistulae in three patients: one male (46 years old) and two females (45 and 53 years old). No murmur was audible in any patient. There was no associated significant coronary artery disease. The feeder arteries to the fistulae for all three patients were left anterior descending coronary artery. One of the patients underwent cardiopulmonary bypass and the fistulae was ligated, due to very strong angina. The diagnosis is mostly incidental during routine coronary arteriography. We concluded that the coronary artery-pulmonary artery fistula might be a cause of angina without audible murmur and may sometimes need surgical ligation.

Grown-up congenital heart disease--medical demands look back, look forward 2000.

A new medical community, the grown-up congenital heart patients--GUCH--has resulted from successes of cardiac surgery over 30-40 years. Many survivors have complicated problems, medical and surgical, demanding experience and expertise neither provided nor organised in most countries. Islands of good care exist with difficulty. The experience of one specialist GUCH unit established for 25 years shows that 55-60% admissions are for complex lesions, particularly after complicated surgery. The patients' overall costs are at least twice those of other cardiac patients. GUCH admissions are about 5-8% of the total, varying according to the population/region served. Supervised medical care for GUCH is equally important in outpatient services, involving 3 times the secretarial time of other cardiac patients, an accessible database and a "helpline" for doctors and patients. This may be life-saving in patients with complex conditions. The GUCH population is ageing, with increasing numbers of complex patients. 30% of admissions now are over 40 years old, and 5% are over 60, confirming that this is an adult medical speciality, not paediatric. Invasive investigations and arrhythmias provide the most frequent reasons for admissions--atrial flutter is the commonest arrhythmia, needing experts when it occurs in Fontan, transposition, etc. Routine coronary arteriography is also important. In cardiac surgery, one in five admissions presents organisational problems. Reoperation, now as many as 9 or 10 times, has to be optimised. Reoperation on left and right outflow tracts-for changing valves and conduits--is more common than first operations. GUCH patients represent a relatively small portion of the whole population. Such patients in a population of 7-8 million need to be concentrated in 1-2 centres, depending on culture, religion, geography, language etc., to provide necessary experience, expertise and education.

Usefulness of the blood lymphocyte count in predicting recurrent instability and death in patients with unstable angina pectoris

S case-control and prospective studies have reported that increased white blood cell (WBC) count is an independent risk factor for coronary heart disease, cardiovascular events, and mortality.1–4 An elevated WBC count has been associated with both a higher risk of developing myocardial infarction and worse outcome in post–myocardial infarction patients.5–7 It has been also reported that relative lymphocyte count may have prognostic significance in patients with known or suspected coronary heart disease.8,9 However, the relation between WBC count and prognosis in patients with unstable angina has not been investigated systematically. In acute coronary syndromes, markers of increased risk, such as cardiac troponin-I exist, which have been shown to be useful for patient risk stratification.10,11 This study assesses the prognostic value of total and differential WBC counts in patients presenting with unstable angina. • • • We studied 71 consecutive patients (44 men) who were admitted to our coronary care unit between September 1996 and June 1997 with the diagnosis of unstable angina (class II-B and III-B according to the Braunwald classification).12 As a control group for baseline WBC measurements, we examined 118 patients (84 men) with chronic stable angina who were admitted for routine coronary arteriography. Patients with unstable angina received conventional treatment with nitrates, heparin, b-adrenergic blockers, calcium antagonists, and aspirin. Clinical decisions were left to the discretion of the managing cardiologist. All patients with unstable angina were followed up for 1 year, or up to the time of elective coronary revascularization in patients who were put on a waiting list for this purpose before hospital discharge. The following were considered to represent study end points: (1) new admission to coronary care unit with unstable angina (Braunwald III-B)12 requiring intravenous drug administration and/or revascularization, (2) myocardial infarction diagnosed according to World Health Organization criteria, and (c) cardiac death. Stable angina was defined as typical exertional chest pain relieved by rest and/or nitrate administration. In all patients with exertional angina, symptoms were stable for at least 3 months before study entry. Exclusion criteria that applied to both groups of patients were: recent (,12 weeks) myocardial infarction, evidence of active infectious disease, inflammatory or immunologic disorders, recent major surgery or trauma, known or suspected neoplastic diseases, treatment with anti-inflammatory or immunosuppressive drugs, renal failure, significant valvular heart disease, and severe heart failure. All patients gave written informed consent before study entry and the study was approved by the local ethics committee. In patients with unstable angina, total and differential WBC counts were measured in morning fasting blood samples withdrawn within the first 24 hours after admission. In those with stable angina, measurements were obtained in fasting blood samples drawn in the morning before coronary angiography. Total and differential WBC counts were determined by a commercially available automated system (STKS Coulter, Beckman Coulters, High Wycombe, United Kingdom) that uses a sample size of up to 8,000 cells. In patients with unstable angina, cardiac troponin-I was measured using a commercially available high-sensitivity immunoassay (AxSYM system, Abbott Laboratories, Abbott Park, Illinois). The value of 0.4 mg/L demonstrating a 95th percentile value of troponin-I measurement in serum from 52 healthy blood donors was subsequently used as the threshold for the analysis. Variables are expressed as mean 6 SD. Odds ratio are expressed with their 95% confidence interval. Proportions have been compared using the chi-square test or 2-tailed Fisher’s exact test. Continuous variables were analyzed using unpaired t tests and Mann-Whitney U tests when appropriate. Logistic regression was used to calculate odds ratio between lymphocyte quartiles. The Cox regression model was used to assess adjusted time-to-event rate curves, where the dependent variable was a risk marker (defined as abnormal cardiac troponin-I and lymphocyte count ,2.40 3 10 lymphocytes/L) and the independent variables were those with p ,0.20 in the univariate analysis. A probability ,0.05 was considered statistically significant. The baseline characteristics of patients with stable and unstable angina are presented in Table I. Unstable angina patients had both higher neutrophil and relative monocyte counts than patients with chronic stable angina. These differences, however, were not statistically significant when adjusted for gender, history of diabetes, past history of myocardial infarction, hypertension, and cholesterol levels (p 5 0.10 and p 5 0.35, respectively). The mean duration of follow-up for unstable angina patients was 13 6 2 months. During that period, 22 unstable angina patients had cardiac events: 18 were readmitted with a new episode of From the Department of Cardiological Sciences, St George’s Hospital Medical School, London, United Kingdom. Prof. Kaski’s address is: Department of Cardiological Sciences, St. George’s Hospital Medical School, Cranmer Terrace, London SW17 0RE, United Kingdom. E-mail: jkaski@sghms.ac.uk. Manuscript received November 22, 1999; revised manuscript received and accepted February 29, 2000.

MILDLY ELEVATED SERUM CREATININE CONCENTRATION CORRELATES WITH THE EXTENT OF CORONARY ATHEROSCLEROSIS

Mildly elevated serum creatinine concentration was proposed to be a marker for increased risk of cardiovascular disease mortality. The aim of our prospective study was to evaluate a possible association between serum creatinine concentration and extent of coronary atherosclerosis together with conventional risk factors for atherosclerosis.Serum creatinine concentration was measured in 40 male patients without overt renal or ischemic renal disease (mean age 53 ± 7 years) with stable or unstable angina undergoing routine coronary arteriography. The extent of coronary atherosclerosis was assessed by Gensini score.In univariate linear regression analysis Gensini score significantly correlated with serum concentrations of apolipoprotein AII (r = −0.3242, P < 0.05) and creatinine (r = +0.3194, P < 0.05), but not with serum concentrations of lipids (total, low- and high-density lipoprotein cholesterol, triglycerides), other apolipoproteins (apo B, apo AI), lipoprotein(a), autoantibodies to oxidatively modified low-density lipoprotein or age, weight and status of smoking, diabetes or hypertension. Multivariate linear regression analysis revealed that elevated serum creatinine was associated with the extent of coronary atherosclerosis independently of conventional risk factors for atherosclerosis.Mildly elevated serum creatinine was probably the marker of generalised vascular disease denoting early nephrovasculopathy in correlation with established atherosclerotic risk factors.

Assessment of Cardiac Risk Before Aortic Reconstruction: Noninvasive Work-Up Using Clinical Examination, Exercise Testing, and Dobutamine Stress Echocardiography Versus Routine Coronary Arteriography

In this prospective study we evaluated the efficacy of a battery of noninvasive tests including clinical evaluation (CE), exercise testing (ET), and dobutamine stress echocardiography (DSE) for assessment of cardiac risk in 90 patients indicated for aortic reconstruction. As the gold-standard reference technique, coronary arteriography was performed in each patient after noninvasive evaluation. The sensitivity of CE was low (61%). ET proved to be more sensitive (71.4%) and highly specific (95.8%) but feasibility (77%) and diagnostic accuracy (42%) were low. DSE demonstrated acceptable sensitivity (78%) and specificity (75.5%) with high feasibility (94.5%) and diagnostic accuracy (100%). None of the four patients with false negative ET results and only one of seven with false-negative DSE required coronary bypass. On the basis of these findings we conclude that a combination of CE and ET with DES, if necessary, can reliably assess cardiac risk before aortic reconstruction. Noninvasive assessment is a reliable alternative to routine coronary arteriography.

Routine Coronary Arteriography Following Thrombolytic Therapy for Acute Myocardial Infarction: An Unsettled Controversy.

Although coronary artery disease remains the leading cause of death in industrialized countries, the management of patients recovering from acute myocardial infarction varies significantly. The issue of routine arteriography and revascularization following thrombolytic therapy remains controversial despite substantial evidence associating infarct-related artery patency with improved cardiac function and survival. Randomized trials of routine intervention after myocardial infarction have generally failed to demonstrate advantages of this invasive approach but methodological problems limit their application to current practice. High-risk patients should be referred for arteriography. While awaiting definitive trials addressing the influence of routine arteriography on patient survival and its cost effectiveness, the management of other patient groups must be individualized.

Comparison of intracoronary Doppler guide wire and transesophageal echocardiography in measurement of flow velocity and coronary flow reserve in the left anterior descending coronary artery

Background The intracoronary Doppler tipped guide wire has been shown to be highly accurate in the measurement of coronary flow velocity (CFV). Recent studies have indicated that blood flow velocity in the left anterior descending coronary artery (LAD) can be determined by transesophageal echocardiography (TEE). The purpose of this study was to compare flow velocity recordings and coronary flow reserve measurements in the LAD by TEE with those obtained by Doppler guide wire. Methods and Results The study population consisted of 14 patients with chest pain and normal coronary arteriograms. After routine coronary arteriography was performed, a 0.014-inch Doppler guide wire was advanced into the proximal part of the LAD. After baseline measurement of coronary flow velocity (CFV) was obtained, 140 μg/kg/min adenosine was administered intravenously for 3 minutes, and the flow velocity was recorded. TEE was performed within 24 hours of the cardiac catheterization. After baseline measurements of CFV in the LAD, heart rate, and blood pressure were obtained, 140 μg/kg/min adenosine was administered intravenously, and the CFV was recorded. Coronary flow reserve was calculated as the ratio of the peak diastolic CFV during adenosine infusion to the peak diastolic CFV at baseline. A good correlation was found ( r = 0.91, p < 0.0001) between CFV by Doppler guide wire and that determined by TEE. A good correlation was also found between the coronary flow reserve assessed by Doppler guide wire and that determined by TEE ( r = 0.92, p < 0.0001). Conclusion Our data indicate that CFV and coronary flow reserve in the LAD can be accurately measured by transesophageal echocardiography. (Am Heart J 1998;135:38-42.)

Absolute volumetric coronary blood flow measurement with digital subtraction angiography.

The problems associated with visual interpretation of coronary arteriograms have been well-documented. There is a need for more physiologic means of assessing coronary artery stenosis during routine coronary arteriography. Volumetric coronary blood flow assessed as a function of time can be a valuable aid in the analysis of functional significance of arterial obstruction. A volumetric coronary blood flow measurement technique was investigated in a swine animal model using phase matched temporal subtraction images. The left anterior descending (LAD) coronary artery of swine animal models were instrumented with an ultrasound flow probe (US) and a vascular occluder producing stenosis. Contrast material injections (2-4 ml/sec for 3 sec) were made into the left coronary ostium during image acquisition. Phase-matched temporal subtraction (DSA) images were used to measure volumetric coronary blood flow in the LAD. In addition, a technique for automatic estimation of iodine calibration slope was also investigated. In 49 independent comparisons, the mean coronary blood flow (FPA) correlated extremely well with the mean US flow (FPA = 0.92US + 1.42 ml/min, r = 0.99, standard error of estimate (SEE) = 4.32 ml/min). Further more, the automatic iodine calibration technique was shown to be very accurate. In conclusion, accurate volumetric coronary blood flow measurements can be made before the onset of significant changes in coronary blood flow due to contrast injection.

Validation of a new UNIX-based quantitative coronary angiographic system for the measurement of coronary artery lesions.

We describe a method of validation of computerized quantitative coronary arteriography and report the results of a new UNIX-based quantitative coronary arteriography software program developed for rapid on-line (digital) and off-line (digital or cinefilm) analysis. The UNIX operating system is widely available in computer systems using very fast processors and has excellent graphics capabilities. The system is potentially compatible with any cardiac digital x-ray system for on-line analysis and has been designed to incorporate an integrated database, have on-line and immediate recall capabilities, and provide digital access to all data. The accuracy (mean signed differences of the observed minus the true dimensions) and precision (pooled standard deviations of the measurements) of the program were determined x-ray vessel phantoms. Intra- and interobserver variabilities were assessed from in vivo studies during routine clinical coronary arteriography. Precision from the x-ray phantom studies (6-In. field of view) for digital images was 0.066 mm and for digitized cine images was 0.060 mm. Accuracy was 0.076 mm (overestimation) for digital images compared to 0.008 mm for digitized cine images. Diagnostic coronary catheters were also used for calibration; accuracy.varied according to size of catheter and whether or not they were filled with iodinated contrast. Intra- and interobserver variabilities were excellent and indicated that coronary lesion measurements were relatively user-independent. Thus, this easy to use and very fast UNIX based program appears to be robust with optimal accuracy and precision for clinical and research applications.

Risk stratification after myocardial infarction in the thrombolytic era.

Most patients with acute myocardial infarction do not receive or are ineligible for thrombolytic therapy, and thus their prognosis is worse than that of the populations studied in the major, randomized, lytic therapy trials. We need to devise a cost-effective strategy with which to appropriately stratify these patients. Simple, easily ascertained clinical variables that are evident soon after hospital admission can identify higher-risk patients, who are likely to be older and less able to adequately complete an exercise test. In some patients, nuclear imaging tests are appropriate; low-dose dobutamine echocardiography and ambulatory ECG monitoring may also have a role. Greater use of routine cardiac catheterization (with assessment of ventricular function) might be the most appropriate way to stratify patients because it may overcome some of the limitations of noninvasive testing, will clearly define high-risk patients, and may facilitate early discharge from the hospital. Left ventricular function and the patency of the infarct-related artery will be determined, and patients with left main coronary disease, significant three-vessel coronary artery disease, and two-vessel coronary disease (especially with proximal left anterior descending coronary artery involvement) will be identified. An aggressive strategy of revascularization to improve survival in appropriate patients may be employed. Greater use of routine coronary arteriography after acute myocardial infarction would inevitably lower the threshold for inappropriate, potentially risky, and expensive further interventions. We need to focus our attention on the most appropriate strategies for the management of patients whose prognosis is worse than the prognosis of those who receive lytic therapy after acute myocardial infarction.

Quantification of Volumetric Coronary Blood Flow With Dual-Energy Digital Subtraction Angiography

As a solution to the well-documented problems associated with visual interpretation of coronary arteriograms, more physiological methods of assessing coronary artery stenosis are being investigated. Volumetric coronary blood flow (BF) can be a valuable aid in the analysis of functional significance of arterial obstruction. The left anterior descending coronary artery (LAD) of 15 anesthetized pigs (40 to 50 kg) was dissected free from the epicardium in its proximal portion, and a transmit-time ultrasound flow probe of the appropriate size was applied. A vascular occluder was positioned distal to the flow probe for flow adjustments. Contrast injections (2 to 4 mL/s for 3 seconds) were made into the left main coronary artery during image acquisition with a motion-immune dual-energy digital subtraction angiography (DE DSA) system. Tissue-suppressed energy-subtracted images were used to generate time-density curves. BF measurements were made in the LAD vascular bed with use of the time-density curve, with consideration that blood was momentarily replaced with contrast during the injection. In 19 comparisons, the mean BF, measured with the use of DE DSA, correlated extremely well with the mean ultrasound flow (DE DSA=0.90 ultrasound+3.10 mL/min, r=.96). Also, contrast injection increased the BF by an average of only 15% during the image-acquisition time interval. Accurate BF measurements can be made with motion-immune DE DSA. The BF measurements can be completed before the onset of significant changes in BF due to contrast injection. Furthermore, it is possible to make the BF measurements during routine coronary arteriography.