A new predictor of restenosis after successful percutaneous transluminal coronary angioplasty in patients with multivessel coronary artery disease

The Predictive Value of ΣΔST/ΔHR Index for Restenosis after Percutaneous Coronary Intervention

Objective

To find out the predictive value of the ΣΔST/ΔHR index for restenosis after percutaneous coronary intervention (PCI).

Method

Subjects of this research were patients who participated in a cardiac rehabilitation (CR) program as six to eight weeks of a hospital-based program after receiving PCI to treat acute coronary syndrome (ACS). The patients received coronary angiography (CAG) at the onset of the ACS and nine months after that, and also received an exercise tolerance test (ETT) at the start of the CR program and several days before receiving a follow-up CAG. In ETT, we used the sum of the ST depression (ΣΔST index) of leads II, III, aVF, V_4-6 as well as the sum of the ΔST/ΔHR (heart rate) (ΣΔST/ΔHR index) in the same leads and the sum of the ΔST/ΔRPP (rate pressure product) (ΣΔST/ΔRPP index) in the same leads. We compared the predictive power of each index of ETT for restenosis after PCI.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value of ΣΔST index were 69%, 47%, 31%, and 82%. The ΣΔST/ΔHR index was 13.7±5.2 in the restenosis group and 9.3±5.6 in the patent group (p=0.017). The sensitivity, specificity, positive predictive value, and negative predictive value of this index were 85%, 63%, 44%, and 92%. The ΣΔST/ΔRPP index were 0.10±0.08 in the restenosis group and 0.06±0.04 in the patent group (p=0.016). The sensitivity, specificity, positive predictive value, and negative predictive value of this index were 54%, 76%, 44%, and 83%.

Conclusion

The ΣΔST/ΔHR index showed a much higher sensitivity and negative predictive value for restenosis after PCI compared to the ΣΔST index.

QT dispersion plus ST-segment depression: a new predictor of restenosis after successful percutaneous transluminal coronary angioplasty

BACKGROUND

ST-segment depression during exercise testing is frequently observed in the absence of restenosis after percutaneous transluminal coronary angioplasty (PTCA).

HYPOTHESIS

With the goal of improving the prediction of restenosis after PTCA, we evaluated the usefulness of ST-segment depression plus QT dispersion (QTd = QTmax - QTmin) during treadmill stress test.

METHODS AND RESULTS

Fifty-six patients (37 men, 19 women, mean age 51 +/- 14 years) were evaluated with treadmill exercise testing and coronary angiography 7 +/- 5 months after PTCA. Treadmill test was positive in 30 patients and negative in 26 patients. At coronary angiography, restenosis was present in 16 patients with positive exercise electrocardiogram (ECG) and in 6 patients with negative exercise ECG. Fourteen patients with a positive stress test did not have restenosis. There was no difference in QTd values between groups at baseline (p > 0.05). Exercise QTd was 63 +/- 9 ms in patients with positive exercise test, 54 +/- 18 ms in patients with negative exercise test (p = 0.003), 71 +/- 13 ms in patients with restenosis, and 53 +/- 17 ms in patients without restenosis (p = 0.001). ST-segment depression during the stress test determined restenosis with a sensitivity of 80% and a specificity of 58%. Sensitivity and specificity of QTd of > or = 60 ms for prediction of restenosis were 83 and 61%, respectively. When QTd of > or = 60 ms was added to ST-segment depression as a condition for positive test, the sensitivity and specificity increased to 91 and 78%, respectively. QT dispersion plus ST-segment depression had higher sensitivity and specificity than either QTd or ST-segment depression alone (p < 0.05).

CONCLUSION

The addition of QTd to ST-segment depression during exercise test improves the diagnostic value and can be used as a noninvasive tool in the diagnosis of restenosis after PTCA.

Utility of routine exercise treadmill testing early after percutaneous coronary intervention

Background

There have been few prospective studies examining the utility of routine exercise treadmill testing (ETT) early after percutaneous coronary intervention (PCI). The objective of this study was to examine the impact of a routine ETT strategy early after PCI on follow-up cardiac events and procedures.

Methods

We examined 136 patients who underwent routine ETT at 6 weeks post-PCI in the ADORE trial. The ETT was classified as positive, indeterminate, or negative. The Duke Treadmill Score (DTS) was calculated for all patients. Follow-up occurred at 9 months.

Results

ETT results at 6 weeks were: 32 (23.5%) positive, 24 (17.6%) indeterminate and 80 (58.8%) negative. At 9 months, the composite event rate was 21.9% in those with a positive ETT, 20.8% in those with an indeterminate ETT and 12.5% in those with a negative ETT (p = 0.25 positive vs. negative ETT). The sensitivity of early ETT for predicting clinical events was 41.2%, the specificity was 73.3%, the positive predictive value was 21.9% and the negative predictive value was 87.5%. At 9 months, the cardiac procedure rate was 18.8% in those with a positive test, 13.0% in those with an indeterminate test, and 6.3% in those with a negative test (p = 0.07 positive vs. negative ETT). In a multivariate logistic regression model, coronary stenting during PCI and a ≥ 85% MPHR achieved were found to be inversely associated with clinical events. However, the DTS did not independently predict clinical events.

Conclusion

Although the statistical power of the study was limited by the small number of clinical events (particularly MI and death), the results of this study support the ACC/AHA guidelines that exercise treadmill testing should not be used routinely after PCI.

QT interval dispersion as a new marker of restenosis after percutaneous transluminal coronary angioplasty of isolated single-vessel coronary artery stenosis

BACKGROUND

There are no reliable non-invasive markers of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The aim of our study was to measure changes in QT interval dispersion after PTCA and to determine whether restenosis subsequently affects QT interval dispersion.

METHODS AND RESULTS

Fifty-six consecutive patients - 41 men and 15 women (mean age: 56.2 +/-8.3 years) - with isolated stenosis of the left anterior descending artery who underwent successful PTCA were studied. A symptom-limited treadmill exercise test was performed within 7 days after PTCA and then again before repeated angiography. Repeated coronary angiography revealed restenosis in 15 patients (26.8%) and no signs of significant stenosis in 41 patients (73.2%). QT interval dispersion in the group of patients with restenosis measured before exercise increased from baseline 34 +/- 7 to 49 +/- 15 ms after 6 months (p < 0.01) and QT interval dispersion measured immediately after exercise increased from baseline 38 +/- 4 to 68 +/- 21 ms after 6 months (p < 0.001). In contrast, patients without restenosis showed no significant changes in QT interval dispersion measured before (baseline: 34 +/- 9 ms; after 6 months 33 +/- 12 ms; p = NS) and immediately after exercise (baseline: 34 +/- 12 ms; after 6 months: 33 +/- 10; p = NS). When QT interval dispersion > or =60 ms (measured 6 months after PTCA procedure) was considered as a potential marker of restenosis, this indicator had very high sensitivity and specificity when measured immediately after exercise (80 and 95% respectively).

CONCLUSIONS

QT interval dispersion significantly increases in the group of patients with documented restenosis and may be a simple, non-invasive marker of restenosis. However, further studies are needed to confirm this observation.

Use of stress-testing modalities after angioplasty or bypass

The use of stress-testing modalities after angioplasty or bypass has been an area of discussion and research since the advent of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG). Issues of when to do which test, and if any, in asymptomatic or symptomatic patients, are not resolved. Stress imaging ETT plays a larger role in this population, but task forces stop short of coming out with any frequency of testing. Cost-effective strategies have not been explored. This article attempts to summarize the results in the literature.

[Diagnostic efficacy of myocardial tomographic imaging in the detection of restenosis after coronary angioplasty]

INTRODUCTION AND OBJECTIVES

To analyze the efficacy of single photon emission tomography (SPET) with 99mTc-compounds for the diagnosis of restenosis of previous percutaneous transluminal coronary angioplasty (PTCA).

PATIENTS AND METHODS

Seventy-one patients (16 women, median age: 60 years, 35 with multivessel disease, 78 arteries with PTCA) with previous PTCA and with coronary angiography performed after scintigraphy were studied. 99mTc-SPET exercise (53 with MIBI and 18 with tetrofosmin) was performed, for clinical reasons, to all patients between one month and 4 years after PTCA. Intravenous dipyridamole was administered simultaneously to 16 patients who had insufficient exercise.

RESULTS

SPET sensitivity, specificity, positive predictive values, negative predictive values and global values were all significantly higher than those obtained with exercise tests (80% vs 63%; p = 0.05; 83% vs 37%; p = 0.001; 91% vs 69%; p = 0.007; 64% vs 31%; p = 0.009, and 81% vs 55%; p = 0.0006, respectively). These results were significantly superior in patients with one vessel disease than in patients with multivessel disease.

CONCLUSIONS

SPET exercise with 99mTc-compounds is a test with a high efficacy for the diagnosis of post-PTCA restenosis, mainly in patients with one vessel disease.

A new criterion combining ST/HR slope and deltaST/deltaHR index for detection of coronary artery disease in patients on digoxin therapy

We evaluated the clinical value of a new index combining deltaST/delta heart rate (HR) index and ST/HR slope for diagnosing coronary artery disease (CAD) in patients on digoxin therapy. Exercise treadmill tests were performed by 72 patients on digoxin therapy. Simple HR-adjusted indexes of ST-segment depression during exercise (deltaST/deltaHR index) and the decline calculated from the final 12 data points relating ST-segment depression to HR (ST/HR slope) were determined. A new index was obtained by subtracting the deltaST/deltaHR index from the ST/HR slope. On thallium scintigraphy, 37 of the 72 patients showed reversible perfusion defects related to the diseased coronary artery. The new index derived from this ST-HR relation was 4.1 +/- 3.6 microV/beats/min in the ischemic group and 1.3 +/- 1.0 microV/beats/min in the group of patients without ischemia (p <0.0001). An ST-HR relation > or = 1.5 was found in 33 of the 37 patients in the ischemic group, and in 7 of the 35 patients without ischemia (p <0.0001). The sensitivity of this criterion for prediction of myocardial ischemia was 89%, the specificity was 80%, and the predictive accuracy was 85%. Thus, this new ST-HR index is useful for detecting CAD in patients on digoxin therapy.