Single-vessel Percutaneous Transluminal Coronary Angioplasty Research Articles

Using Nonparametric Control Chart to Build a Surveillance Mechanism of Medical Care Expenses

According to the Diagnosis Related Groups (DRGs) policy initiated in Taiwan in 2010, hospital payments within a given diagnosis group should be fixed, making it critical for hospitals to monitor growth of medical care costs. This study investigates how to monitor the cost of unusual factors on single vessel percutaneous transluminal coronary angioplasty (PTCA) and attempts to build a surveillance mechanism for DRGs medical care expenses. This investigation sampled objects from the National Health Insurance Database of Taiwan during 2010. This study analyzed variation in fees of single vessel PTCA in selected medical centers, and chose inpatients over 17 years old as objects for study. This study used two nonparametric control charts, Nonparametric Shewhart control chart and Nonparametric Exponentially Weighted Moving Average control chart, contributing further to constructing the mechanism for surveying medical care expenses. The selected medical center underwent construction changes, and medical expenses rose gradually increased following August 2010. The selected medical center thus had good fiscal control of single vessel PTCA surgery, and the medical expenses for most cases were lower than the standardized payment rate of National Health Insurance. This study used a Nonparametric Shewhart control chart to analyze monthly medical costs and identify unusual months. This approach was suitable for monitoring large changes in process. This study also used the Nonparametric Exponentially Weighted Moving Average control chart to estimate the current data and long-term trend data to reduce Nonparametric Shewhart control chart error, because this could not be achieved by analyzing past long-term trends. Nonparametric Exponentially Weighted Moving Average control chart had better detection of small process changes and achieved early awareness of gradual financial losses. This study used two nonparametric control charts to build the surveillance mechanism for DRGs. This study provided effective information to medical providers seeking to maintain health care quality and obtain sufficient profits to enable sustainable development by developing a mechanism for surveying medical care expenses.

The dependence of patient dose on factors relating to the technique and complexity of Interventional Cardiology procedures

Dose-area product (DAP) measurements were conducted for 168 coronary angiography (CA) and 89 single vessel percutaneous transluminal coronary angioplasty (PTCA) to examine the factors influencing patient dose beyond the X-ray exposure parameters. It was found that for CA, the DAP increases with the number of catheters used and with the number of vessels with stenosis. DAP values for patients with a prior bypass surgery, were higher compared to those without such a medical record to surgery. In PTCA, the use of coronary stents did not enhance the patient radiation dose significantly. Noticeable differences were found in the percentage contribution of each projection to the total DAP between the three types of single vessel PTCA. Finally low variations in DAP were found among the cardiologists performing both procedures.

Differential response of coronary collateral channels to atrial pacing and balloon occlusion at angioplasty.

Collateral channels can protect from infarction, even in the presence of a total or sub-total occlusion. Acute re-occlusion following restoration of flow may still lead to ischaemia or infarction. It is unclear whether collaterals respond differently to tachycardia-induced stress and balloon inflation. This study compared the response of collateral-dependent viable myocardium to repetitive atrial pacing with the response to multiple balloon occlusions during percutaneous transluminal coronary angioplasty (PTCA). Fifteen patients undergoing elective single vessel PTCA with well-developed collateral channels supplying the target vessel were recruited. Patients underwent two periods of incremental atrial pacing (P(1); P(2)) followed by two 90-s balloon inflations (I(1); I(2)). Collateral flow velocity was assessed by Doppler flow wire across the target lesion. Evidence of ischaemia was obtained from monitoring of surface ST-segments and by chest pain scores recorded on a visual analogue scale. Retrograde and 'aggregate' flow velocities were significantly lower during I(1) and I(2) than either P(1) or P(2). Reduction in flow velocity was most marked during I(1) compared with P(1) or P(2). Chest pain score was lower during P(2) than P(1) (3.8 +/- 3.5 versus 5.5 +/- 3.0, P < 0.02), although flow velocity was unchanged. Collateral flow velocity is significantly higher during tachycardia-induced stress than balloon occlusion. Restoration of antegrade flow by balloon inflation results in a further reduction in flow during a second inflation, suggesting a functional down-regulation of the collateral channels. Ischaemic symptoms are attenuated with repetitive pacing independent of collateral flow, suggesting an additional preconditioning response.

Clinical outcome after multivessel coronary stent implantation

Background Percutaneous transluminal coronary angioplasty (PTCA) has been shown to be an effective therapy for multivessel coronary artery disease, although more frequent acute complications and an increased need to repeat revascularization than with single-vessel PTCA continue to be limitations. Intracoronary stent placement has been shown to reduce the rate of acute complications and the need for subsequent revascularization. We sought to evaluate the outcome among patients undergoing successful multivessel coronary intervention with stents. Methods The participants were 175 patients without coronary artery bypass grafts who underwent multivessel coronary revascularization in which stent placement was attempted in all treated segments from January 1992 through March 1998 at our institution. Clinical and angiographic characteristics and outcomes were analyzed. Results Stent placement was attempted for 428 coronary lesions. The angiographic success rate was 100%. Modified American College of Cardiology–American Heart Association type B2 and C lesions accounted for 74.5% of the lesions. Three patients (1.7%) died in the hospital. No patient had Q-wave myocardial infarction or needed coronary artery bypass grafting. Procedural success was achieved for 172 patients (98.3%). The Kaplan-Meier probability of freedom from death or myocardial infarction at 12 months was 96.6%, of any revascularization was 81.7%, and of death, myocardial infarction, and any revascularization combined was 79.8%. The use of long-acting nitrates at 12 months was reduced (34.3% versus 19.1%, P = .01). Conclusions Multivessel coronary stent placement is associated with an excellent procedural success rate despite a high rate of adverse lesion characteristics and a high event-free survival rate during the follow-up period. The likelihood that revascularization will not have to be repeated during the first follow-up year is significantly better than that for historic controls of multivessel PTCA. (Am Heart J 1999;138:1105-10.)

Improved detection of posterior myocardial wall ischemia with the 15-lead electrocardiogram

Background: A routine 12-lead electrocardiogram is commonly obtained to evaluate for possible acute myocardial infarction during the initial screening of patients with chest discomfort. Posterior myocardial infarction is commonly missed because it is not usually visible in the standard leads. In this study, we compared the sensitivity and specificity of posterior chest leads (V7, V8, and V9) and 12-lead electrocardiography in detecting posterior injury pattern during single-vessel percutaneous transluminal coronary angioplasty. Methods and Results: Three posterior chest leads in addition to the routine 12-lead electrocardiogram were monitored simultaneously during single-vessel percutaneous transluminal coronary angioplasty of the right, circumflex, and left anterior descending coronary arteries in a total of 223 patients. Posterior injury patterns (95%) were detected mostly during circumflex coronary occlusion. Posterior leads were able to detect injury pattern in 49% (36 of 74) of patients, whereas the 12-lead electrocardiogram was able to detect only 32% (P < .04). When all 15 leads were used to detect all ST elevations, sensitivity increased to 57%, with a specificity of 98% for the circumflex coronary artery. If maximal ST depressions in leads V2 to V3 are considered to be from posterior myocardial injury, then the overall sensitivity is increased to 69%. Conclusions: Posterior leads significantly increased the detection of posterior injury pattern compared with the standard 12-lead electrocardiogram. Using all 15 leads significantly further improved the detection of circumflex coronary–related injury pattern over the standard 12-lead electrocardiogram. (Am Heart J 1999;138:934-40.)

Preprocedural serum levels of C-reactive protein predict early complications and late restenosis after coronary angioplasty

OBJECTIVESWe sought to investigate whether early and late outcome after percutaneous transluminal coronary angioplasty (PTCA) could be predicted by baseline levels of acute-phase reactants.BACKGROUNDAlthough some risk factors for acute complications and restenosis have been identified, an accurate preprocedural risk stratification of patients undergoing PTCA is still lacking.METHODSLevels of C-reactive protein (CRP), serum amyloid A protein (SAA) and fibrinogen were measured in 52 stable angina and 69 unstable angina patients undergoing single vessel PTCA.RESULTSTertiles of CRP levels (relative risk [RR] = 12.2, p < 0.001), systemic hypertension (RR = 4.3, p = 0.046) and female gender (RR = 4.1, p = 0.033) were the only independent predictors of early adverse events. Intraprocedural and in-hospital complications were observed in 22% of 69 patients with high serum levels (>0.3 mg/dl) of CRP and in none of 52 patients with normal CRP levels (p < 0.001). Tertiles of CRP levels (RR = 6.2, p = 0.001), SAA levels (RR = 6.0, p = 0.011), residual stenosis (RR = 3.2, p = 0.007) and acute gain (RR = 0.3, p = 0.01) were the only independent predictors of clinical restenosis. At one-year follow-up, clinical restenosis developed in 63% of patients with high CRP levels and in 27% of those with normal CRP levels (p < 0.001).CONCLUSIONSPreprocedural CRP level, an easily measurable marker of acute phase response, is a powerful predictor of both early and late outcome in patients undergoing single vessel PTCA, suggesting that early complications and clinical restenosis are markedly influenced by the preprocedural degree of inflammatory cell activation.

Impact of restenosis 10 years after coronary angioplasty.

The aim of the study was to compare the 10-year follow-up results of patients with or without restenosis following single-vessel percutaneous transluminal coronary angioplasty (PTCA). A total of 313 patients with successful PTCA (> or = 20% reduction in luminal diameter narrowing without acute complications) and a control angiography 6 months after PTCA were included in the study. Events during the follow-up period were defined as death, myocardial infarction, bypass surgery, or repeat PTCA. Statistical evaluation was performed by the Fisher test, logistic regression, and life-table analysis. Restenosis (loss of > 50% of the initial gain and diameter stenosis of 50%) was found in 87 (28%) patients. During follow-up, 11 patients (5%) without restenosis (group A) and 11 (13%) patients with restenosis (group B) died (P < 0.05). In group A, 17 (8%) patients and in group B, 11 (13%) patients suffered myocardial infarction (ns); 17 group A (8%) patients and 25 (29%) group B patients had bypass surgery (P < 0.0001), and 34 (15%) group A patients and 55 (63%) group B patients underwent repeat PTCA (P < 0.0001). Logistic regression analysis identified restenosis as an independent risk factor that increases the risk of death 2.8-fold (P = 0.02), bypass surgery 5.6-fold (P < 0.0001), and repeat PTCA 10-fold (P < 0.0001). We conclude that patients with restenosis had a poorer long-term outcome than patients without restenosis. Although most patients with restenosis underwent repeat PTCA, the survival rate without any serious adverse events was only 59%, compared with 83% in patients without restenosis (P < 0.0001).

Accuracy of Treadmill Exercise Electrocardiography in Detecting Restenosis Following Single-Vessel Percutaneous Transluminal Coronary Angioplasty

To develop an improved method for diagnosing restenosis using treadmill exercise electrocardiography (ECG) following percutaneous transluminal coronary angioplasty (PTCA), we prospectively evaluated 46 patients who underwent PTCA for the treatment of single-vessel coronary artery disease and who did not have a history of myocardial infarction. Treadmill exercise ECG and coronary angiography were performed 3 months after PTCA to determine their accuracy in diagnosing restenosis based on standard ST-segment depression criteria, the difference between the maximum ST-segment depression before and 3 months after PTCA (≤0.5 mm: positive; >0.5 mm: negative), and the difference between ΣST-segment depression before PTCA and 3 months after PTCA (≤1.5 mm: positive; >1.5 mm: negative). The sensitivity, specificity, and diagnostic accuracy of standard ST-segment depression criteria were 65%, 66%, and 65%, respectively. The sensitivity, specificity, and accuracy for the difference in maximum ST-segment depression were 77%, 76%, and 76%, respectively, whereas the values for the difference in ΣST-segment depression were 77%, 83%, and 80%, respectively. Based on these results, we conclude that using the difference between ST-segment depression before and after PTCA improves the accuracy of treadmill exercise ECG for diagnosing restenosis.

Cardiac troponin I to diagnose percutaneous transluminal coronary angioplasty-related myocardial injury

The purposes of the present study were to evaluate cardiac troponin I (cTnI) in the diagnosis of percutaneous transluminal coronary angioplasty (PTCA)-related myocardial injury in comparison with cardiac troponin T (cTnT) and creatine kinase (CK) MB mass concentration, and to investigate the frequency of myocardial injury, as indicated by myocardial protein release, after clinically symptomless side-branch occlusion (SBO) which may occur in the proximity of the attempted stenosis. The final study population comprised 80 patients undergoing elective, single vessel PTCA. Blood samples were drawn before, 6, 24 and 48 h after PTCA. cTnI, cTnT and CKMB mass baseline values were within the reference intervals in all patients (cTnI < 0.1 μg/l, cTnI < 0.2 μg/l, CKMB < 5 μg/l). Two patients presented with primary failure of PTCA, and visually successful PTCA was performed in all remaining patients. Seven patients (four with SBO) subsequently developed acute myocardial infarction (AMI). Symptomless SBO occurred in 16 patients. In controls ( n = 55) there were no significant increases in cTnI, cTnT, or CKMB concentrations compared with baseline values, and all markers stayed within their reference intervals. In half the patients with symptomless SBO ( n = 8) all markers were slightly to moderately increased, in two additional patients only CKMB was elevated (cTnI: 0.1–1.0 μg/l; cTnT: 0.25–0.81 μg/l and CKMB: 7.9–25.6 μg/l). In the majority of patients with primary failure or AMI we found pronounced increases in all tested markers (cTnI: 0.2–12.0 μg/l; cTnT: 0.44–12.10 μg/l; CKMB: 19.2–423.0 μg/l). The results of this study indicate that cTnI is comparably useful to cTnT or CKMB mass for diagnosing myocardial injury in PTCA patients. From our results a preference for one of the tested parameters cannot be clearly derived. Post-procedural cTnI, cTnT, and CKMB mass values are not higher than baseline values in uncomplicated cases, whereas AMI after PTCA leads to pronounced marker increases. SBO, even when symptomless, leads frequently (in about half the patients) to slight marker increases.

The natural history of unheralded complex coronary plaques

Objectives. This study sought to assess the behavior of unheralded complex lesions in patients with no previous history of acute coronary ischemia.Background. Angiographically complex coronary stenoses appear to originate from plaque disruption and are associated with rapid progression early and late after acute coronary events. Complex lesions may occur without symptoms, but neither the incidence nor the behavior of these unheralded complex lesions is known.Methods. We studied 222 patients with chronic stable angina who were on a waiting list for single-vessel percutaneous transluminal coronary angioplasty of an unoccluded lesion and underwent repeat angiography immediately before the procedure as part of routine practice or shortly after a coronary event. Patients with a previous episode of myocardial infarction or unstable angina were not included. Angiograms were analyzed quantitatively and qualitatively using established methods. A change of ±15% stenosis severity or total coronary occlusion defined categoric change.Results. At first angiography, there were 52 unheralded complex target lesions (23%) and 170 smooth target stenoses (77%). Stenosis severity did not differ between complex and smooth target lesions at first and second angiography at a mean (±SD) interval of 7 ± 4 months. At follow-up, seven complex lesions had progressed (14%) compared with six smooth lesions (4%, p < 0.02). Total occlusion developed in four complex lesions and one smooth lesion. Overall, complex stenoses progressed by 3 ± 13% compared with 0.5 ± 7% in the smooth stenoses (p = 0.15). Complex stenoses were 4.2 times more likely to progress than smooth stenoses (95% confidence interval 1.2 to 15.2 [Cornfields method]). Clinical events developed in seven patients. One complex lesion regressed and became smooth, and three smooth stenoses became complex at follow-up.Conclusions. Morphologically complex stenosis can develop without an episode of acute coronary ischemia and are relatively common in patients awaiting single-vessel angioplasty. Our study demonstrates that like their clinically heralded counterparts, these unheralded complex stenoses are at higher risk of progression than smooth stenoses.

Assessment of myocardial area at risk by technetium-99m sestamibi during coronary artery occlusion: comparison between three tomographic methods of quantification

The aim of this study was to directly compare three currently used quantitative methods of analysis of technetium-99m sestamibi images in patients with selective balloon-induced transmural ischaemia. The area at risk (AR) was assessed in 19 patients undergoing single-vessel percutaneous transluminal coronary angioplasty by injecting the 99mTc-sestamibi at the time of coronary artery occlusion during balloon inflation. After imaging, the patients were classified according to localization of the perfusion defect as having anteroseptal (group I, 11 patients) or posterolateral defects (group II, eight patients). The planimetric technique based on polar maps, proposed by Verani et al. (J Am Coll Cardiol, 1988) (method A), the method described by Tamaki et al. (Circulation, 1982) (method B) and the technique validated by O Connor et al. (Eur J Nucl Med, 1990) (method C) were tested. Three threshold values of 45%, 50% and 60% of the maximum left ventricular count were used to define the limits of the perfusion defect. The mean values of the AR calculated by the three techniques with the original cut-off level (method A=16.5%+/-12.9; method B=10.4%+/-7.6%; method C=29.6%+/-15.7%) were statistically different (one-way analysis of variance: P<0.001; paired t test: method A vs B, P=0.003; method B vs C and method A vs C, P<0.0001). There was no significant difference between the mean values of the AR estimated by the three methods using the same cut-off levels. The use of 60% of the maximum left ventricular count provided the best correlation between the techniques (method A vs B, r=0.95; method B vs C, r=0.92; method A vs C, r=0.95). Nevertheless, a difference >10% between the values of AR assessed by the three methods was found in four subjects. There was no significant difference between the three methods in the evaluation of AR in the subjects of group I and group II. Reproducibility was good for all methods. It is concluded that the three methods of analysis of the AR by 99mTc-sestamibi SPET imaging showed comparable performance and good reproducibility using the same cut-off level. The location of perfusion defect does not affect the comparability of the three techniques. We suggest the use of a cut-off level of 60% for all three methods in the assessment of the AR by 99mTc-sestamibi SPET imaging.

Maximal myocardial perfusion by videodensitometry in the assessment of the early and late results of coronary angioplasty: Relationship with coronary artery measurements and left ventricular function at rest

In the assessment of the acute results of percutaneous transluminal coronary angioplasty (PTCA), myocardial perfusion at maximal vasodilatation theoretically has fewer limitations than the coronary flow reserve measurements and quantitative coronary angiography. The purpose of this study was to compare the myocardial perfusion to the measurements of the severity of the lesion (minimal luminal diameter and percent area stenosis) and to relate it to the changes of left ventricular function after PTCA. Regional myocardial perfusion was assessed during intracoronary papaverine, using the inverse mean transit time of contrast medium (1/Tmn), before, 15 min after, 18-24 hr after, and 6 months after successful single-vessel PTCA in 14 patients with stable angina. Left ventricular angiography (before angioplasty, 18-24 hr after, and 6 months later) was analysed by area-length and centerline methods. Immediately after PTCA, 1/Tmn increased from 0.14 +/- 0.07 sec-1 to 0.21 +/- 0.09 sec-1 (P = .001). Maximal myocardial perfusion remained higher than the pre-PTCA value the day after angioplasty (1/Tmn of 0.23 +/- 0.09 sec-1), while it reduced to near pre-PTCA values at follow-up (1/Tmn of 0.16 +/- 0.05 sec-1). Before PTCA, three out of ten patients had ejection fraction of < 65%, and seven had mild-to-moderate hypokinesis. The day after PTCA the ejection fraction and the regional dysfunction improved significantly. The change in ejection fraction 18-24 hr after PTCA did not correlate with minimal luminal diameter and percent area stenosis and correlated slightly with the improvement of perfusion (r = 0.54, P = .10). At follow-up left ventricular function deteriorated in the whole group, despite the persistence of angiographic success of PTCA, possibly because of changes in the loading condition. Coronary artery stenosis measurements and 1/Tmn failed to correlate with the left ventricular function. Given the difficulties in routine application of the analysis of time-density curves, the measurement of minimal luminal diameter remains a more practical assessment of the results of the intervention. However, the improvement of myocardial perfusion may give more information than coronary artery dimensions of the early recovery of left ventricular function.

901-100 Prognostic Value of Technetium-99m Sestamibi Myocardial Tomography One Month After Successful Angioplasty: Comparison to Peri-procedural Angiographic and Intracoronary Doppler Flow Velocity Parameters

The prognostic value of post-PTCA stress technetium-99m sestamibi (MIBI) scintigraphy relative to peri-procedural coronary angiographic and flow parameters has not been established following successful percutaneous transluminal coronary angioplasty (PTCA). To this end, 34 consecutive pts aged 57 ± 14 yrs were followed for 13 ± 10 months after successful single-vessel PTCA (mean % diameter stenosis [OS] from 78 ± 15% to 24 ± 11%; P &lt; 0.001) for cardiac events (death = 1, Ml = 1, CABG = 2, repeat PTCA = 6). Basal intracoronary 0.018”Doppler flow wire distal/proximal average peak velocity ratio (mean dip APV ratio = 1.0 ± 0.7) and hyperemic distal coronary flow velocity reserve (mean CFR = 1.7 ± 0.6) were obtained immediately after PTCA. Same-day rest-stress MIBI tomograms performed 4.7 ± 3.7 weeks after PTCA were blindly interpreted to quantify total (1.6 ± 2.5). fixed (0.9 ± 1.7) and reversible (0.8 ± 1.5) defects per PTCA vessel perfusion bed. Multivariate Cox regression modeling determined the relative risk (RR) of cardiac events:Empty CellEvent RateRR (95% CI)Chi Squarep valuePost-PTCA %DS &gt; 30%15%03 (0.l–17)1.940.16PTCA zone rev. MIBI50%5.5 (1.0–10)2.930.08Distal CFR &lt; 2.060%8.3 (2.5–171)2.560.07d/p APV ratio &lt; 153%6.2 (1.2–104)3940.04Rev. MISI defect + ratio &lt; 160%2.3 (1.5–36)4220.03We conclude that post-PTCA cardiac events are predicted by residual abnormalities of coronary flow and stress MIBI myocardial perfusion. Combining these variables can enhance their predictive value for adverse post-PTCA outcomes. which frequently occur despite initial angiographic “success”.

810-1 Enhanced Inflammatory Acute Phase Response After Percutaneous Coronary Angioplasty in Patients with Unstable Angina

Elevated levels of C-reactive protein (CRP), a sensitive marker of inflammation, are independent predictors of short-term prognosis in patients (pts) with unstable angina (UA). The causes of the acute phase response in UA, however, are still unknown. Percutaneous transluminal coronary angioplasty (PTCA) is an useful model for the assessment of the effects of plaque disruption and myocardial ischemia on the acute phase response. Serum levels of CRP were measured in 21 pts with chronic stable angina (SA) (G 1) and in 22 pts with UA refractory to maximal medical treatment (G2), undergoing single-vessel PTCA. Venous blood samples were taken immediately before PTCA and 6, 24, 48, 72 hours after the end of the procedure. CRP values are expressed as median and range. Before PTCA, CRP was elevated (&gt; 3 mg/l) in 2/21 G1 pts (10%) and in 16/22 G2 pts (73%) (p &lt; 0.001): it was 2.4 (2–4.4) mg/l in Gl and 8 (2.4–29) mg/l in G2 (p &lt; 0.001). After PTCA, CRP increased to a peak value of 2.6 (2–16.4) mg/l 38 ± 13 hrs after the procedure in Gl, and to a peak value of 19.9 (2.8–49.4) mg/l 32 ± 14 hrs after the procedure in G2 (p &lt; 0.001. G1 vs G2). A significant increase in CRP after PTCA, defined as an increase &gt; 50% the basal values, was observed in 8/21 Gl pts and in 16/22 G2 pts (p &lt; 0.05). The percentage increase of CRP after PTCA was higher in G2 than in Gl (180 ± 239%, range 0–925% vs 118 ± 176%, range -13–489%, p &lt; 0.05). No difference in coronary stenosis severity before PTCA (84 ± 9% vs 89 ± 8%), residual stenosis (30 ± 7% vs 29 ± 10%), number of ballon inflations (6 ± 3.4 vs 5.3 ± 3.2), total inflation time (365 ± 202 vs 413 ± 197 sec) and mean inflation pressure (5 ± 0.9 vs 5 ± 1 atm) was found between Gl and G2 pts. Our study shows that the plaque disruption and the brief periods of myocardial ischemia caused by PTCA elicit a variable individual inflammatory acute phase response, that is greater in UA compared to SA pts. These data suggest a higher inflammatory responsiveness in patients with UA, that may playa pathogenetic role in acute coronary syndromes, and help explaining the higher rate of acute complications typically observed in patients with unstable angina undergoing PTCA.

Digital angiographic assessment of the physiological changes to the regional microcirculation induced by successful coronary angioplasty.

Impulse response analysis of digital coronary angiographic images calculates a parameter known as the mean transit time of the microcirculation (Tmicro). This has been shown to accurately assess the regional microcirculatory response to proximal stenosis in relation to flow. Our goal was to apply impulse response analysis to patients undergoing successful angioplasty and to quantify the induced physiological changes with respect to quantitative angiographic measurements of stenosis dimensions. We studied 24 patients before and after successful single-vessel percutaneous transluminal coronary angioplasty (PTCA). Minimal luminal stenosis area was increased from 0.9 +/- 0.6 before PTCA to 4.1 +/- 1.3 mm2 after PTCA (P < .0001). In all patients this was accompanied by an increase in the inverse of Tmicro (Tmicro-1), from 8.5 +/- 3.0 to 26.5 +/- 9.0 min-1 (P < .0001) with a linear correlation between Tmicro-1 and minimal luminal stenosis area (r = .73; SEE = 7.74). Stenosis flow reserve, estimated by integration of stenosis dimensions, increased in all patients from 1.8 +/- 1.0 to 4.5 +/- 0.4 after PTCA (P < .01). A comparison of Tmicro-1 with stenosis flow reserve revealed a nonlinear relation. In 16 patients undergoing PTCA of the left anterior descending or circumflex artery, contrast injections into the left main stem allowed simultaneous measurements of Tmicro-1 in the adjacent, nonstenotic artery. Adjacent artery Tmicro-1 did not change after PTCA (25.8 +/- 6.2 compared with 25.6 +/- 6.8 min-1 before PTCA; P = NS); moreover, Tmicro-1 of the dilated artery measured after PTCA was equivalent to the nonstenotic adjacent artery, indicating normalization of microcirculatory responses. These data suggest that Tmicro-1 determined by digital angiographic impulse response analysis of a single contrast injection under resting flow conditions may be a practical method to assess the regional microcirculatory response to changes in stenosis severity effected by coronary angioplasty.

Percutaneous Transluminal Coronary Angioplasty in Elderly Patients

Fifty-six patients aged 75 years and older underwent percutaneous transluminal coronary angioplasty (PTCA) at our institution from 1984 to 1991. The average age was 76.7 +/- 1.5 years, and 84% of the patients were males. Single-vessel disease occurred in 21 patients, double-vessel disease in 16, and three-vessel disease in 19 patients. The mean left ventricular ejection fraction was 57 +/- 5%, and 8 patients had an ejection fraction of < 40%. The anginal functional class was I in 1 patient, II in 3, III in 6, and IV in 46 patients. Single-vessel PTCA was attempted in 43 patients, two-vessel PTCA in 8, and three-vessel PTCA in 5 patients. Revascularization was complete in 35% of the patients, incomplete in 57, and no revascularization was obtained in 8% of the patients. Ninety-one percent of the patients had a successful procedure. In 5 patients there was severe dissection, 1 patient died, 1 patient had an acute myocardial infarction, and 1 patient had emergency bypass surgery. Long-term follow-up (6-96 months, mean 21 +/- 4) in the 51 successfully treated patients revealed late cardiac death in 1 patient, repeated PTCA for restenosis in 9, and coronary bypass surgery in 2 patients. Twenty-two patients were asymptomatic, 12 had improved symptoms, and 5 remained symptomatic. PTCA appears to be a safe and effective treatment in elderly patients with one- and two-vessel disease, with excellent long-term results. Age is not a contraindication to PTCA. The results in elderly patients with three-vessel disease are less encouraging.

Aspirin, but not heparin, suppresses the transient increase in thromboxane biosynthesis associated with cardiac catheterization or coronary angioplasty

Objectives. We sought to study the dose dependence of in vivo suppression by aspirin of enhanced thromboxane biosynthesis in the setting of coronary angioplasty and to evaluate the effects of heparin and aspirin during cardiac catheterization.Background. Percutaneous transluminal coronary angioplasty induces a controlled injury of the intima of the diseased arterial segment, with rapid deposition of platelets at the site of dilation. Thus, it provides a clinical model of intracoronary platelet activation.Methods. The urinary excretion of a major enzymatic metabolite of thromboxane A2, 11-dehydro-thromboxane B2, was measured in 57 patients with stable coronary artery disease undergoing cardiac Catheterization (n = 28) or elective single-vessel percutaneous transluminal coronary angioplasty (n = 29). Three consecutive urine collections were obtained from all patients before during and after either procedure. Patients undergoing Catheterization were treated with the following regimens: a) no aspirin for ≥10 days and no heparin (n = 12); b) no aspirin for ≥10 days but heparin, 10,000 IU, at the time of Catheterization (n = 5); c) aspirin, 300 mg/day, for at least 5 days (n = 1). Patients undergoing coronary angioplasty were randomly assigned to short-term treatment with aspirin given as a) 75 mg/day for ≥5 days before angioplasty (n = 11); b) 300 mg/day for ≥3 days before angioptesty (n = 9); or c) 300 mg/day for ≥3 days before angiopiasty followed by 1,000 mg during angioplasty (n = 9).Results. In patients undergoing Catheterization, urinary 11-dehydro-thromboxane B2excretion (pg/mg creatinine) increased from 563 ± 481 (mean ± SD) to 1,684 ± 1,332 in the absence and from 620 ± 191 to 1,588 ± 597 in the presence of heparin. No increase was observed in the group receiving aspirin (from 240 ± 141 to 215 ± 115). In patients undergoing coronary angioplasty treated with aspirin, 75 mg/day, urinary 11-dehydro-thromboxane B2averaged 180 ± 112, 223 ± 178 and 294 ± 260, respectively, before, during and after the procedure. At 300 mg/day, the corresponding values were 185 ± 48, 217 ± 70 and 197 ± 93. In patients also receiving aspirin, 1,000 mg, during angioplasty, 11-dehydro-thromboxane B2averaged 151 ± 66, 138 ± 43 and 133 ± 77, respectively.Conclusions. Enhanced thromboxane biosynthesis associated with cardiac Catheterization or coronary angioplasty can be largely suppressed by low dose aspirin. This finding is consistent with the view that this alteration reflects platelet activation.

Early and Late Exercise Testing: Usefulness After Percutaneous Transluminal Coronary Angioplasty

Seventy-five patients 36 to 68 years of age were studied after undergoing successful single-vessel percutaneous transluminal coronary angioplasty (PTCA). In all cases exercise tests (ETs) were made prior to the procedure and 2 to 4 days and 6 months thereafter. Angiographic controls were performed on patients with positive ET. Both early and late ET carried out after dilatation lasted significantly longer. Patients were able to tolerate greater work loads and their heart rates and arterial blood pressures also were higher. The ETs conducted prior to PTCA were positive in 62 patients. After dilatation, the early test was positive in 18 and the late test, in 10. Angiographic controls revealed restenosis in 75 percent of patients with single-vessel disease and positive ET. Thus, the results of ETs in patients with single-vessel disease tend to become negative after successful PTCA. Early and late positive ETs are associated with restenosis, while negative ETs indicate a good prognosis.

Factors influencing outcome of regional wall motion after successful elective single-vessel percutaneous transluminal coronary angioplasty

Factors influencing outcome of regional wall motion after successful elective single-vessel percutaneous transluminal coronary angioplasty

Transient myocardial ischemia stimulates atrial natriuretic factor release

Atrial natriuretic factor release during transient myocardial ischemia was investigated in 29 patients with coronary artery disease and symptoms of angina (Canadian Cardiovascular Association classes II–III). Eleven patients (group I) underwent single-vessel percutaneous transluminal coronary angioplasty. Repeat determinations of mean pulmonary artery wedge pressure and blood sampling from pulmonary artery for atrial natriuretic factor measurements were performed at baseline, and at 2, 5, and 15 minutes after percutaneous transluminal coronary angioplasty was begun. Baseline atrial natriuretic factor levels (34.6 ± 4.5 pg/ml) rose to 56.3 ± 7.3 pg/ml ( p = 0.02) and decreased at 5 minutes (43.7 ± 5.7 pg/ml, not significant) and 15 minutes (35.3 ± 4.4 pg/ml, not significant). Changes in atrial natriuretic factor concentrations were significantly correlated with those in mean pulmonary artery wedge pressure (2 minutes: r = 0.69, p = 0.02; 5 minutes: r = 0.90, p < 0.001). In group II ( n = 10) the increase in atrial natriuretic factor after dye load occurred later (baseline: 25.8 ± 2.1; 60 minutes: 40.6 ± 2.6 pg/ml; p = 0.005) than that observed in group I after percutaneous transluminal coronary angioplasty. In group III, atrial natriuretic factor during angina rose as early (baseline 11.3 ± 1.3; 5 minutes: 20 ± 2.3 pg/ml; p = 0.006) as after percutaneous transluminal coronary angioplasty. Results indicate that transient myocardial ischemia stimulates atrial natriuretic factor release, probably through changes in cardiac function.