Presence Of Reversible Perfusion Defects Research Articles

Clinical usefulness of epicardial adipose tissue in patients with high-intermediate pre-test probability for coronary artery disease.

Epicardial adipose tissue (EAT) is thought to be associated with the extension and severity of coronary artery disease (CAD), and echocardiographic measurement of EAT thickness is considered to be a possible cardiovascular risk indica-tor. The European Society of Cardiology Task Force recommends further non-invasive testing in patients with an intermediate pre-test probability (PTP) for the diagnosis of CAD. We sought to evaluate the clinical usefulness of performing EAT measurements in patients with a high-intermediate PTP. Patients referred to an outpatient clinic with stable chest pain symptoms, with PTP for CAD between 66% and 85%, were included in the study. Echocardiographic measurement of the EAT was identified as the echo-free space between the outer wall of the myocardium and the visceral layer of the pericardium. Single-photon emission computed tomography (SPECT) was performed in all patients. The diagnosis of CAD was based on the presence of reversible perfusion defects on SPECT. A total of 126 patients (76 men, 60.3%) with a mean age of 65.3 ± 9.1 years were recruited. The EAT thickness was 7.3 ± 0.7 mm in patients with positive SPECT and 6.2 ± 0.6 mm in patients with negative SPECT (p < 0.001). Multivariable analysis revealed higher rates of positive SPECT in patients with higher EAT (odds ratio [OR] 9.80; 95% confidence interval [CI] 3.72-25.79; p < 0.001), and receiver operating characteristic curve analysis showed that the greatest specificity was obtained when the cut-off value of EAT thickness was 6.75 mm (sensitivity 76%; specificity 74%). In patients with high-intermediate PTP, EAT is a useful measurement that may assist in risk stratification.

The influence of clopidogrel on ischemia diagnosed by myocardial perfusion stress testing

BackgroundClopidogrel is a platelet adenosine receptor antagonist which can influence coronary vascular tone and thus can potentially interfere with myocardial perfusion imaging. We investigated whether clopidogrel can hamper the diagnosis of ischemia in patients undergoing myocardial perfusion testing. MethodsData from a database of 6349 myocardial perfusion stress tests were analyzed. Using a propensity analysis, patients who were taking clopidogrel were compared with patients not taking clopidogrel for the presence of reversible perfusion defects on myocardial single-photon emission computed tomography scans. ResultsOf the 6349 tests, the stress technique was adenosine in 2713 patients and exercise in 3636. At the time of the stress test, 277 (4.3%) of the patients were taking clopidogrel. The odds ratio (OR) for patients taking clopidogrel to have a reversible perfusion defect was 2.75 (95% confidence interval [CI] 2.09-3.62; P < .01). After adjusting for the propensity to take clopidogrel, the OR was 1.06 (CI 0.76-1.49; P = .73) for patients undergoing adenosine stress tests and 1.60 (CI 0.85-3.00; P = .14) for patients undergoing exercise stress tests. ConclusionsWe found no evidence that the use of clopidogrel decreases the likelihood of ischemia on adenosine or exercise stress myocardial perfusion scans.

Prognostic utility of ischemic response in functional imaging tests (SPECT or stress echocardiography) in low-risk unstable angina patients.

The aim of this study is to determine the ability of ischemic response in imaging stress tests (single-photon emission computed tomography [SPECT] or stress echocardiography [SE]) to predict events in low-risk unstable angina patients. Three hundred and fifty-nine patients with unstable angina (< 24 h), asymptomatic at admission, without ST-segment elevation or depression, normal troponins, and undergoing SPECT (n = 188) or SE (n = 171) during hospitalization (median = 1 day) were included. A positive imaging test (IMAGING+) was defined as the presence of reversible perfusion defects or wall motion abnormalities in at least 2 contiguous segments. Multivariate models were constructed using these results and clinical variables to predict events at 6 months. Ninety-nine (27%) patients had IMAGING+, 72/188 (38%) in SPECT and 27/17 (16%) in SE (p < 0.0001). Events occurred in 84 (23%) patients: 4 had myocardial infarction, 47 new hospitalizations due to angina and 33 coronary artery revascularizations. Independent predictors of coronary artery disease were: IMAGING+ (OR: 6.4, 95% CI: 3.4-11.8, p < 0.0001), history of coronary artery disease (OR: 2.5, 95% CI: 1.2-5.2, p < 0.02) and TIMI risk (OR: 1.5, 95% CI: 1.1-2.2, p < 0.03). In low-risk unstable angina patients, an ischemic response in functional stress tests (SPECT or SE) was associated with adverse events and severe coronary artery disease.

Variables that influence the indication of a second myocardial perfusion gated-SPECT after a normal stress-rest gated SPECT

ObjectiveThe objective of this study was to investigate predictor variables at the moment of normal stress-rest myocardial perfusion gated SPECT for the indication of a second gated SPECT. Materials and methodsA prospective, single center cohort study was conducted. We evaluated 2326 consecutive patients (age 63.6±13 years, 57.3% females) without perfusion defects and with normal left ventricular ejection fraction on a myocardial perfusion gated SPECT. Clinical and stress test variables were studied to predict indication of a second gated SPECT and presence of reversible perfusion defects in the second gated SPECT. ResultsDuring a mean follow-up of 3.6±2 years a second gated SPECT was performed in 286 patients (12.3%). Independent predictor variables of a second gated SPECT were presence of three or more cardiovascular risk factors (χ2: 5.510; HR: 1.4; p=0.019), previous acute myocardial infarction (χ2: 3.867; HR: 1.4; p=0.049), previous coronary revascularization (χ2: 41.081; HR: 2.5; p<0.001), and a positive stress test (χ2: 8.713; HR: 1.5; p=0.003). Observation of perfusion defects in the 280 patients in whom a second stress-rest gated SPECT was performed was more likely in male patients (χ2: 4.322; HR: 1.9; p=0.038) who had a first pure pharmacological gated-SPECT (χ2: 7.182; HR: 2.6; p=0.007). ConclusionsIn patients with a first normal myocardial perfusion gated SPECT, various clinical factors and variables derived from the stress test affect the indication of a second gated SPECT and the presence of ischemia in the latter.

Variables que influyen en la indicación de una segunda gated-SPECT de perfusión miocárdica después una gated-SPECTde estrés-reposo normal

The objective of this study was to investigate predictor variables at the moment of normal stress-rest myocardial perfusion gated SPECT for indication of a second gated SPECT.A prospective, single center cohort study was conducted. We evaluated 2326 consecutive patients (age 63.6 ± 13 years, 57.3% females) without perfusion defects and with normal left ventricular ejection fraction on a myocardial perfusion gated SPECT. Clinical and stress test variables were studied to predict indication of a second gated SPECT and presence of reversible perfusion defects in the second gated SPECT.During a mean follow-up of 3.6 ± 2 years a second gated SPECT was performed in 286 patients (12.3%). Independent predictor variables of a second gated SPECT were presence of three or more cardiovascular risk factors (χ(2): 5.510; HR: 1.4; p=0.019), previous acute myocardial infarction (χ(2): 3.867; HR: 1.4; p=0.049), previous coronary revascularization (χ(2): 41.081; HR: 2.5; p<0.001), and a positive stress test (χ(2): 8.713; HR: 1.5; p=0.003). Observation of perfusion defects in the 280 patients in whom a second stress-rest gated SPECT was performed was more likely in male patients (χ(2): 4.322; HR: 1.9; p=0.038) who had a first pure pharmacological gated-SPECT (χ(2): 7.182; HR: 2.6; p=0.007).In patients with a first normal myocardial perfusion gated SPECT, various clinical factors and variables derived from the stress test affect the indication of a second gated SPECT and the presence of ischemia in the latter.

The clinical usefulness of carotid ultrasonography in patients with an inconclusive exercise treadmill stress test result

BackgroundAlthough a treadmill exercise stress testing (EST) is often the first-line screening procedure for subjects with an intermediate probability of coronary artery disease (CAD), one limitation of this test is the high rate of inconclusive tests that result from borderline exercise-induced ST changes. The carotid intima media thickness (CIMT) correlates well with atherosclerosis. The purpose of this study was to evaluate the clinical usefulness of performing CIMT measurements in patients with an inconclusive EST. MethodsSymptomatic patients without history of vascular disease and with inconclusive EST result were included. Inconclusive results were defined as the presence of horizontal or downsloping ST-segment depression between 0.5 and 0.9mm or 1.0 and 1.4mm upsloping ST-segment depression. After inconclusive EST regarding electrocardiographic changes, the measurements of the CIMT and myocardial perfusion imaging study (MPS) were performed in all patients. The CIMT was measured at the posterior wall of the common carotid artery. The diagnosis of CAD was based on the presence of reversible perfusion defects on exercise MPS. ResultsA total of 87 patients (57 men) with a mean age of 58.9±7.2 years were enrolled. The MPS was positive in 18 patients. The CIMT in patients with positive MPS was significantly greater than in patients with negative MPS. The CIMT was 0.82±0.33mm in patients with positive MPS and 0.63±0.21mm in patients with negative MPS (p=0.004). Receiver operating characteristic curve analyses revealed that the greatest specificity was obtained when the cut-off value of CIMT was set at 0.66mm (sensitivity 39%; specificity 72.5%; positive predictive value 27%; negative predictive value 82%). ConclusionIn patients with inconclusive electrocardiographic changes during EST, CIMT was a useful measurement to prevent alternative more expensive and invasive tests. Additionally, mean CIMT is useful for screening patients with an inconclusive EST result to exclude CAD.

Detection and prognostication of reversible perfusion abnormalities and scar in patients with suspected coronary ischemia: Results from a pilot study comparing stress cardiac magnetic resonance and positron emission tomography

Methods Consecutive patients who underwent stress PET Rubidium perfusion were prospectively enrolled to undergo stress CMR for assessment of ischemia and infarction. Sum rest and sum stress scores were qualitatively graded using a 16-segment model in both PET and CMR. CMR protocol consisted of cine steady-state free precession imaging for left ventricular function, rest and adenosinestress first pass perfusion at 0.075 mmol/kg, and late gadolinium enhancement (LGE) imaging for myocardial scar. Results Ninety patients were enrolled and underwent CMR within 60 days of the PET. Mean age was 61 years and 60% were male. Thirty-one had a significant reversible perfusion defect(ReVPD)seen on stress CMR. Concordance rate for presence of ReVPD was 71% (see Table 1). For the 26 patients with discordant findings for perfusion, 23 (88%) patients were noted to have a RevPD by CMR. Concordance rate for the presence of myocardial scar was 71% (Table 2). In the 26 patients with discordant findings for scar, 24 (92%) patients were noted to have subendocardial scar by CMR. At a medium follow-up of 3.0 years (IQR 2.2 years), RevPD by both PET and CMR were associated with all major adverse events (PET: HR 2.7, P = 0.05; CMR: HR 6.9, P < 0.001). With absence of RevPD and absence of scar, PET and CMR were associated with a negative hard-event (cardiac death or acute myocardial infarction) rate of 96% and 99%, respectively. Among the 25 patients with abnormal CMR (reversible defect or scar) but normal PET, there were 3 cardiac deaths and 3 AMIs during the follow-up.

Changes in Myocardial Perfusion Correlate With Deterioration of Left Ventricular Systolic Function in Chronic Chagas' Cardiomyopathy

This study aimed at analyzing the association between myocardial perfusion changes and the progression of left ventricular systolic dysfunction in patients with chronic Chagas' cardiomyopathy (CCC). Pathological and experimental studies have suggested that coronary microvascular derangement, and consequent myocardial perfusion disturbance, may cause myocardial damage in CCC. Patients with CCC (n = 36, ages 57 +/- 10 years, 17 males), previously having undergone myocardial perfusion single-positron emission computed tomography and 2-dimensional echocardiography, prospectively underwent a new evaluation after an interval of 5.6 +/- 1.5 years. Stress and rest myocardial perfusion defects were quantified using polar maps and normal database comparison. Between the first and final evaluations, a significant reduction of left ventricular ejection fraction was observed (55 +/- 11% and 50 +/- 13%, respectively; p = 0.0001), as well as an increase in the area of the perfusion defect at rest (18.8 +/- 14.1% and 26.5 +/- 19.1%, respectively; p = 0.0075). The individual increase in the perfusion defect area at rest was significantly correlated with the reduction in left ventricular ejection fraction (R = 0.4211, p = 0.0105). Twenty patients with normal coronary arteries (56%) showed reversible perfusion defects involving 10.2 +/- 9.7% of the left ventricle. A significant topographic correlation was found between reversible defects and the appearance of new rest perfusion defects at the final evaluation. Of the 47 segments presenting reversible perfusion defects in the initial study, 32 (68%) progressed to perfusion defects at rest, and of the 469 segments not showing reversibility in the initial study, only 41 (8.7%) had the same progression (p < 0.0001, Fisher exact test). In CCC patients, the progression of left ventricular systolic dysfunction was associated with both the presence of reversible perfusion defects and the increase in perfusion defects at rest. These results support the notion that myocardial perfusion disturbances participate in the pathogenesis of myocardial injury in CCC.

Long-term prognostic value of CFVR and FFR versus perfusion scintigraphy in patients with multivessel disease

In this multicentre study, we investigated the long-term prognostic value of intracoronary derived haemodynamic parameters compared with the results of myocardial perfusion scintigraphy (MPS). Patients (n=191) who were referred for angioplasty of a severe lesion in the presence of an intermediate lesion in another coronary artery were included. MPS was performed to determine the presence of reversible perfusion defects in the area of the intermediate lesion. Coronary flow velocity reserve (CFVR), and additionally fractional flow reserve (FFR; n=129), were determined distal to the intermediate lesion; CFVR >/=2.0 and FFR >/=0.75 were considered negative. In total 67 events occurred in 49 patients (3 deaths, 9 MI, 9 CABG, 46 PTCA) during a mean of 793 days follow-up. Event-free survival was 63% for MPS, 79% for CFVR, and 79% for FFR if a negative test result was obtained. The relative risk was 1.2 (not significant) for MPS, 2.2 (p=0.001) for CFVR, and 2.4 (p=0.004) for FFR. Selective evaluation of an intermediate lesion using CFVR or FFR allows more adequate risk stratification in patients with multivessel disease than MPS. A CFVR <2.0 or a FFR <0.75 was associated with a significant increase of the occurrence of cardiac events during long-term follow-up, predominantly associated with revascularisation. (Neth Heart J 2007;15:369-74.).

Can measurement of the intima-media thickness of the carotid artery improve the diagnostic value of exercise stress tests?

Objective — The diagnostic value of the exercise electrocardiogram (ECG) for the detection of coronary artery disease is hampered by a high proportion of equivocal results, especially in asymptomatic patients. The intima-media thickness of the carotid artery correlates well with the degree of atherosclerosis, also in other vascular beds, such as the coronary arteries. The aim of this study is to evaluate whether measurements of intima-media thickness can improve the diagnostic value of stress ECG in the detection of coronary artery disease.Methods — Patients without a history of vascular disease and with equivocal exercise stress ECG results were included.The intima-media thickness was measured with high resolution echography at the posterior wall of the common carotid artery, using an automated edge-tracking method. The diagnosis of coronary artery disease was based on the presence of reversible perfusion defects on exercise MIBI-scintigrams.Results — A total of 90 patients (46 men, 44 women) with a mean age of 53.7 years were included. The MIBI-scintigraphy was positive in 17. There was no difference in mean intima-media thickness between MIBI positive and MIBI negative patients (635.76 ± 84.56 μm and 643.89 ± 107.06 μm, respectively, p = 0.8). Using multiple regression analysis, neither intima-media thickness measurements, nor classic risk factors could predict the result of MIBI-scintigraphy. Intima-media thickness was mainly influenced by age and hypertension.Conclusions — In this study, neither intima-media thickness measurements, nor classic risk factors could improve the diagnostic value of stress ECG in the detection of coronary artery disease. In case of equivocal stress results, additional cardiovascular imaging techniques remain recommended.

Associations Among Cardiorespiratory Fitness, Framingham Risk Score and Myocardial Ischemia

Cardiorespiratory fitness (CRF), Framingham risk score (FRS) and myocardial ischemia are all associated with coronary heart disease (CHD) risk. However, the interrelationships among these risk indicators are less understood. PURPOSE: To examine the associations among CRF, FRS, and the presence of inducible myocardial ischemia. METHODS: Participants were 379 men (mean ± SD, age 57 ± 9 years) who were free of known CHD and who completed a maximal exercise test, an electron beam tomography scan and myocardial perfusion imaging between 1998 and 2004. These tests were conducted within 180 days (median=1 day, 25th%, 75th% =0-12 days) of each other. MET levels of CRF were based on a symptom-limited maximal exercise test. CRF was denned as low (≤ 8.4 METs) or moderate-high (>8.4 METs). FRS was based on measured clinical data and was categorized as low (<10%) and moderate-high (≥ 10%) risk. Inducible myocardial ischemia was denned as the presence of reversible perfusion defects. RESULTS: Approximately 12% (n=45) of all participants had inducible myocardial ischemia. The prevalence of myocardial ischemia was higher in men with low compared with moderate-high CRF (26% vs. 9.5%, p <0.001) and in men with a moderate-high FRS compared with a low FRS (15% vs. 7.8%, p = 0.03). Logistic regression analysis showed that after adjusting for differences in baseline examination year, the presence of coronary artery calcium and family history of CHD, the relative odds (95% CI) of inducible ischemia were 0.24 (0.11–0.55) in men with moderate-high CRF compared to those with low CRF. The inverse relation between CRF and inducible ischemia tended to exist regardless of FRS. In men with low FRS, the odds ratio (95% CI) for inducible ischemia in men with moderate-high CRF was 0.35 (0.07–1.6) compared to men with low CRF. In men with moderate-high FRS, the odds ratio (95% CI) for inducible ischemia in men with moderate-high CRF was 0.20 (0.07–0.55) compared to men with low CRF. CONCLUSION: CRF, a surrogate measure of cardiac function, is inversely associated with inducible myocardial ischemia, independent of FRS. Promoting CRF appears to have effects beyond its benefits on the various components of Framingham risk analysis.

Relation of Myocardial Perfusion Defects and Nonsignificant Coronary Lesions by Angiography With Insights from Intravascular Ultrasound and Coronary Pressure Measurements

Several studies have demonstrated a correlation between myocardial ischemia and severity of coronary lesions as determined by intravascular ultrasound (IVUS) and fractional flow reserve (FFR) measurements. However, their value for the assessment of mild coronary stenoses that are associated with myocardial perfusion abnormalities has not been well studied. The objective of this study was to prospectively compare the results of myocardial perfusion as determined by exercise/dipyridamole myocardial single-photon emission computed tomography with IVUS and FFR measurements in patients who had angiographically mild coronary stenosis (< 50% diameter stenosis by quantitative coronary angiography). Forty-eight patients who had stable coronary disease (61 +/- 11 years of age; 6 women) were included. All had mild coronary stenosis in the proximal/middle segment of > or = 1 coronary artery and had undergone maximal exercise myocardial technetium-99m tetrofosmin single-photon emission computed tomography within 48 hours before coronary angiography. IVUS measurements included lesion lumen area, external elastic membrane area, lesion plaque burden (calculated as external elastic membrane minus lumen area, divided by external elastic membrane, and multiplied by 100), and lumen area stenosis (calculated as reference lumen area minus lesion lumen area, divided by reference lumen area, multiplied by 100). Fifty-three coronary lesions were studied, with a mean percent diameter stenosis of 34.9 +/- 7.9% on angiography. Myocardial perfusion defects were demonstrated by single-photon emission computed tomography in 11 patients (12 myocardial regions) with no differences in lesion percent diameter stenosis compared with those without perfusion defects. The presence of reversible perfusion defects was associated with a higher lesion plaque burden as evaluated by IVUS (67.4 +/- 8.1% vs 60.2 +/- 9.3%, p = 0.01). FFR values did not differ in the presence or absence of perfusion defects (0.90 +/- 0.06 vs 0.92 +/- 0.07, respectively; p = NS). In conclusion, plaque burden as determined by IVUS may partly explain the presence of myocardial perfusion defects in cases of angiographically nonsignificant coronary lesions. However, the high FFR values associated with these lesions suggest that other mechanisms, such as endothelial/microvascular dysfunction, might also account for perfusion abnormalities in these patients.

Prognostic value of quantitative stress myocardial perfusion imaging in unstable angina patients with negative cardiac enzymes and no new ischemic ECG changes

Limited data are available on the value of quantitative stress myocardial perfusion imaging (MPI) in patients with unstable angina. In this report we sought to study the long-term prognostic value of quantitative stress MPI in patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes. The study population consisted of 136 patients who were hospitalized at the Methodist Hospital, Houston, Tex, with unstable angina and subsequently underwent MPI before discharge. Cox proportional hazards (regression) analysis was performed to identify clinical and MPI predictors of hard cardiac events (death or nonfatal myocardial infarction). During a mean follow-up of 31 +/- 17 months, 20 patients (15%) sustained either cardiac death (n = 12) or nonfatal myocardial infarction (n = 8). The significant multivariate predictors of cardiac events were the total perfusion defect size ( P = .002), the presence of reversible perfusion defects ( P = .01), and the presence of multiple perfusion defects ( P = .03). The perfusion defect size was significantly larger in patients with events than in those without events (21% +/- 20% vs 12% +/- 14%, P = .002). Kaplan-Meier analysis showed that cardiac events were much more likely to develop in patients with defects involving 15% or more of the left ventricle than in those with defects involving less than 15% of the left ventricle ( P = .003). In patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes, quantitative stress MPI provides powerful prognostic information that can be used in the risk stratification of these patients.

Exercise-induced prolongation of the infarct-related Q-waves as a marker of myocardial viability in the infarcted area

Objective: It is known that exercise-induced ischemia in patients with coronary artery disease (CAD) may produce QRS prolongation in the surface electrocardiogram (ECG). To investigate the presence of exercise-induced Q-wave prolongation in patients with single-vessel CAD and Q-wave myocardial infarction (MI), in association with the presence of reversible perfusion defects during thallium scintigraphy in the infarcted area. Methods: 107 consecutive patients (89 males, mean age 56±8 years) were evaluated. All patients underwent coronary arteriography, maximal treadmill exercise testing and thallium-201 scintigraphy. Q-wave duration was measured both before exercise testing and during maximal heart rate from 12-lead ECGs recorded with a paper speed of 50 mm/s. Results: Only 57 out of the 107 studied patients showed reversible perfusion defects in the infarcted area during thallium scintigraphy. Q-wave duration was significantly increased from the resting to the stress ECG (ΔQ-wave duration) in patients with reversible perfusion defects in the infarcted areas (10±13 ms), but not in patients with fixed defects in the infarcted zone (−2.0±5 ms, p<0.01). The sensitivities and the specificities of Q-wave prolongation, ST segment elevation, and the combination of ST segment elevation with ST segment depression in the reciprocal leads for the detection of myocardial viability in the infarcted area were 82%, 48%, 29% and 88%, 50%, and 90%, respectively. Conclusions: Exercise-induced Q-wave prolongation is demonstrated in those patients with single-vessel CAD and a recent MI who show reversible perfusion defects in thallium scintigraphy. Exercise-induced Q-wave prolongation was found to be a sensitive and specific ECG marker for the detection of myocardial viability in the infarcted area.

Analysis of referral patterns, predictive accuracy, and impact on patient management of myocardial perfusion imaging in a new nuclear cardiology laboratory

Background. Most of the published data on myocardial perfusion imaging (MPI) come from large tertiary-referral medical centers with extensive experience in cardiac imaging as well as a large volume of procedures. Whether the results of MPI remain as reliable in new nuclear cardiology laboratories with smaller volumes of procedures is unknown. The purpose of this study was to analyze the referral patterns, predictive accuracy, and impact of MPI on clinical practice in a newly opened nuclear cardiology laboratory. Methods and Results. We performed a prospective study on all patients referred for MPI at our nuclear cardiology laboratory during its first year of operation. Patients were followed up for 3 months after the MPI study to determine whether they underwent coronary angiography. The study population consisted of 334 patients. Their mean age was 56 ± 10 years, and 80% were men. Of the patients, 30% were asymptomatic, 29% had angina, and only 6% had recent acute myocardial infarction or unstable angina. Fifty-one patients (fifteen percent) were subsequently referred for coronary angiography. The positive and negative predictive values of MPI were 91% and 86%, respectively. The presence of reversible perfusion defects ( P = .02) and the presence of multiple perfusion defects ( P = .01) on MPI were the most important determinants of subsequent referral to coronary angiography. Conclusions. MPI stress testing retains its high diagnostic accuracy in a new nuclear cardiology laboratory with a relatively small volume of procedures. Furthermore, MPI findings in this population had a strong impact on the clinical practice of the referring physicians in terms of subsequent referral to coronary angiography. (J Nucl Cardiol 2003;10:148-53)

Fractional flow reserve, absolute and relative coronary blood flow velocity reserve in relation to the results of technetium-99m sestambi single-photon emission computed tomography in patients with two-vessel coronary artery disease

OBJECTIVESWe sought to perform a direct comparison between perfusion scintigraphic results and intracoronary-derived hemodynamic variables (fractional flow reserve [FFR]; absolute and relative coronary flow velocity reserve [CFVR and rCFVR, respectively]) in patients with two-vessel disease.BACKGROUNDThere is limited information on the diagnostic accuracy of intracoronary-derived variables (CFVR, FFR and rCFVR) in patients with multivessel disease.METHODSDipyridamole technetium-99m sestambi (MIBI) single-photon emission computed tomography (SPECT) was performed in 127 patients. The presence of reversible perfusion defects in the region of interest was determined. Within one week, angiography was performed; CFVR, rCFVR and FFR were determined in 161 coronary lesions after intracoronary administration of adenosine. The predictive value for the presence of reversible perfusion defects on MIBI SPECT of CFVR, rCFVR and FFR was evaluated by the area under the curve (AUC) of the receiver operating characteristics curves.RESULTSThe mean percentage diameter stenosis was 57% (range 35% to 85%), as measured by quantitative coronary angiography. Using per-patient analysis, the AUCs for CFVR (0.70 ± 0.052), rCFVR (0.72 ± 0.051) and FFR (0.76 ± 0.050) were not significantly different (p = NS). The percentages of agreement with the results of MIBI SPECT were 76%, 78% and 77% for CFVR, rCFVR and FFR, respectively. Per-lesion analysis, using all 161 measured lesions, yielded similar results.CONCLUSIONSThe diagnostic accuracy of three intracoronary-derived hemodynamic variables, as compared with the results of perfusion scintigraphy, is similar in patients with two-vessel coronary artery disease. Cut-off values of 2.0 for CFVR, 0.65 for rCFVR and 0.75 for FFR can be used for clinical decision-making in this patient cohort. Discordant results were obtained in 23% of the cases that require prospective evaluation for appropriate patient management.

Dipyridamole thallium imaging

The objective of this study was to determine whether routine performance of dipyridamole thallium imaging adds to the power of a careful clinical evaluation in the risk stratification of patients undergoing major vascular surgery. In this retrospective study, 115 cases evaluated by dipyridamole thallium imaging before major vascular surgery were reviewed. Patients were assigned to a high-risk cohort if they had a history of congestive heart failure or evidence of previous myocardial infarction. Six (8%) patients from the high-risk cohort developed major cardiovascular complications. Reversible perfusion defects, present in 67% of the high-risk patients, did not predict complications. None of the patients in the low-risk cohort developed complications despite the presence of reversible perfusion defects in 33%. Patients in the high-risk cohort who underwent cardiac catheterization and selective coronary bypass grafting were uniformly free of perioperative complications. The extent and severity of fixed or reversible thallium perfusion did not predict the occurrence of cardiovascular complications. However, three patients were denied surgery following an unacceptable cardiovascular risk assessment based on clinical findings and multiple reversible thallium perfusion defects. In low-risk patients, screening with dipyridamole thallium can identify patients with redistribution defects whose risk of perioperative ischemic events can be reduced by intensifying perioperative anti-ischemic management. If the patient is in the high-clinical-risk subgroup, screening with dipyridamole thallium does not identify a cohort with negligible perioperative risk; thus, further evaluation of these patients by cardiac catheterization should be considered.