Diagnostic value of exercise electrocardiography and angina after coronary artery stenting. Benestent Study Group

Comparison of quantitative coronary angiography and first-pass perfusion magnetic resonance imaging for the detection of an impaired coronary perfusion in nonsevere coronary stenosis

PURPOSE

To compare quantitative coronary angiography (QCA) and first-pass perfusion magnetic resonance imaging (FPP-MRI) in symptomatic patients with nonsevere coronary stenosis to detect a reduced coronary flow velocity reserve (CFVR).

MATERIALS AND METHODS

In 35 patients, FPP-MRI and CFVR measurements were performed in 40 coronary arteries with a diameter stenosis (DS) <70% by QCA. From FPP-MRI a myocardial perfusion reserve index (MPRI) was calculated. CFVR was calculated as the ratio of the average peak flow velocity during infusion of adenosine and at rest and was considered reduced if <2. Diagnostic performance of MPRI and DS to detect a reduced CFVR was compared by receiver operating characteristic (ROC) curve analysis.

RESULTS

CFVR was reduced in 16 coronary arteries (40%). Mean DS did not differ in coronary arteries with a reduced CFVR (41.0% +/- 13.3) and a normal CFVR (36.5% +/- 12.3; P = 0.281). Mean MPRI was lower in coronary arteries with a reduced CFVR (1.12 +/- 0.12) compared to a normal CFVR (1.33 +/- 0.2; P < 0.001). Sensitivity, specificity, and area under the ROC curve (AUC) were higher for MPRI (81%, 79%, 0.84) than for DS (56%, 58%, 0.60).

CONCLUSION

FPP-MRI detects impaired CFVR in symptomatic patients with nonsevere coronary stenosis more accurately than QCA and can identify patients with symptomatic ischemia.

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.

Coronary artery stent thrombosis associated with exercise testing

Chest pain following coronary artery stenting is common, yet finding the cause can be difficult. Exercise testing has long been used in the assessment of chest pain, but its usefulness in patients who have recently undergone coronary artery stenting is in doubt. A case of exercise testing appearing to precipitate acute stent thrombosis in a patient several weeks post-coronary artery stenting is reported and compared to a similar case in the literature. The role of exercise testing in the assessment of chest pain early after coronary artery stenting is then reviewed.

Myocardial perfusion imaging following percutaneous coronary intervention: the importance of restenosis, disease progression, and directed reintervention

Percutaneous coronary intervention (PCI) has become a mainstay in the treatment of patients with coronary artery disease. Currently, more than one million coronary angioplasty and stent implantation procedures are performed annually. Although increasingly complex lesions and higher risk patients are being successfully treated percutaneously, restenosis and disease progression continue to cause significant morbidity. Restenosis occurs in approximately one-third of patients, one-half of who remain asymptomatic, while disease progression occurs at rates approaching 7% per year. Despite technological advances, unadjusted mortality rates have actually increased since the mid-1980s, and the current annual risk of a major adverse cardiac event following PCI is 5% to 7%. Although randomized clinical trials are needed to more definitively show a benefit, when performed six or more months following PCI, myocardial perfusion imaging reliably identifies patients most at risk of a poor long-term outcome. Directed reintervention can have a salutary impact on the prognosis of these patients. In view of recent data showing a positive impact of imaging and reintervention in patients after PCI, current guidelines should be reassessed.

Short-term risk after initial observation for chest pain

Few studies have evaluated the necessity of immediate stress testing after observation for chest pain. The purpose of this study was to assess the safety of outpatient stress testing after discharge from a chest pain unit. We hypothesized that discharge from a chest pain unit before stress testing is associated with a low rate of short-term adverse outcomes. This was a retrospective chart review of managed care patients discharged from the chest pain unit before the performance of stress testing. Records were reviewed for the occurrence of adverse cardiac outcomes before an outpatient stress test up to 60 days post-discharge. Primary outcomes were defined as death or myocardial infarction, and secondary outcomes as readmission for chest pain evaluation, unstable angina, or congestive heart failure. Three hundred forty-four patients were identified. One hundred sixty-six patients had either a recent prior stress test (17) or an outpatient test (149) performed within 60 days of discharge. During that time, 2 patients (0.6%) had a fatal out-of-hospital cardiac event, and there were 27 subsequent chest pain visits to the Emergency Department by 24 patients (7.0%). Nine patients (2.6%) were admitted to the hospital and 10 (2.9%) were readmitted to the observation unit for chest pain. We conclude that patients who have negative serial electrocardiograms and enzyme testing in a chest pain unit are at low risk for short-term cardiac events. Appropriately selected patients may be discharged for subsequent outpatient testing.

Clinical and angiographic factors associated with asymptomatic restenosis after percutaneous coronary intervention

BACKGROUND

Angiographic restenosis after percutaneous coronary interventional procedures is more common than recurrent angina. Clinical and angiographic factors associated with asymptomatic versus symptomatic restenosis after percutaneous coronary intervention were compared.

METHODS AND RESULTS

All patients with angiographic restenosis from the BENESTENT I, BENESTENT II pilot, BENESTENT II, MUSIC, WEST 1, DUET, FINESS 2, FLARE, SOPHOS, and ROSE studies were analyzed. Multivariate analysis evaluated 46 clinical and angiographic variables, comparing those with and without angina. The 10 studies recruited 2690 patients who underwent percutaneous revascularization and 6-month follow-up angiography (86% of those eligible). Restenosis (>/=50% diameter stenosis) occurred in 607 patients and was clinically silent in 335 (55%). Male sex (P=0.008), absence of antianginal therapy with nitrates (P=0.0002) and calcium channel blockers (P=0.02) at 6 months, greater reference diameter after the procedure (P=0.04), greater reference diameter at follow-up (P=0.004), and lesser lesion severity (percent stenosis) at 6 months (P=0.0004) were univariate predictors of asymptomatic restenosis. By multivariate analysis, only male sex (P=0.04), greater reference diameter at follow-up (P=0.002), and lesser lesion severity at 6 months (P=0.0001) were associated with restenosis without angina.

CONCLUSIONS

Approximately half of patients with angiographic restenosis have no symptoms. The only multivariate predictors of silent restenosis at 6 months were male sex, greater reference diameter at follow-up, and lesser lesion severity on follow-up angiography.

Detection of coronary restenosis by exercise electrocardiography thallium-201 perfusion imaging and coronary angiography in asymptomatic patients after percutaneous transluminal coronary angioplasty

Noninvasive detection of restenosis in patients remaining asymptomatic after percutaneous transluminal coronary angioplasty (PTCA) remains a major clinical problem. The value of exercise electrocardiography (ECG) and exercise-redistribution thallium-201 single-photon emission computed tomography (SPECT) in detecting restenosis in such patients remains uncertain. Discordances between these tests and coronary angiography is a common situation. We studied 179 consecutive patients remaining asymptomatic after successful PTCA (208 vessels), who underwent 6 +/- 2 months of exercise ECG, SPECT, and coronary angiography. We sought to assess the diagnostic value of the noninvasive tests compared with coronary angiography, and identify the determinants of discordances between the tests. Restenosis (diameter stenosis >50%) was detected in 39% of patients and in 37% of vessels. The overall sensitivity, specificity, and accuracy for exercise ECG and SPECT in detecting restenosis in individual vessels were, respectively, 53% versus 63% (p = 0.06), 59% versus 77% (p = 0.0001), and 57% versus 72% (p = 0. 0001). On multivariate analysis, positive exercise ECG was associated with higher heart rate response (p = 0.02), incomplete revascularization (p = 0.004), and angiographic restenosis (p = 0. 03), whereas positive SPECT was associated with incomplete revascularization (p = 0.02), infarct-related artery PTCA (p = 0.01), and angiographic restenosis (p = 0.0001). Accuracies of the 2 tests were not significantly different in patients with incomplete revascularization or PTCA of an infarct-related vessel. Overall, SPECT is more accurate than exercise ECG in detecting asymptomatic restenosis. Nevertheless, incomplete revascularization and PTCA of an infarct-related artery could cause reversible perfusion defects regardless of restenosis, reducing the diagnostic value of SPECT in such patients.

Cost-efficacy modeling of functional testing with perfusion imaging to detect asymptomatic restenosis following percutaneous transluminal coronary angioplasty

The objective of this study was to perform a theoretical cost-efficacy analysis on the use of routine functional testing with perfusion imaging to identify patients with asymptomatic restenosis following percutaneous transluminal coronary angioplasty (PTCA) procedures. Approximately 50% of patients with restenosis following PTCA are asymptomatic. Routine functional testing is commonly performed at 3 to 6 months to identify these patients. The cost-efficacy associated with this strategy is unknown. Theoretical models were constructed based on assumed costs for functional testing (U.S. $1,300) and coronary angiography (U.S. $3,000). Restenosis rates were assumed to be 40%, and half of patients with restenosis were assumed to be asymptomatic. To provide a range of costs to identify a patient with asymptomatic restenosis, three scenarios were constructed based on the diagnostic test characteristics of functional testing. Sensitivity analyses were performed using a range of costs for functional testing, restenosis rates, and proportion of patients with restenosis who are asymptomatic. Depending on the diagnostic accuracy of functional testing, it costs $8,200 to $22,400 to identify an asymptomatic patient with restenosis following PTCA. The cost to identify a patient with asymptomatic restenosis varies inversely with the rates of restenosis. When restenosis rates are < 20%, the cost to identify a patient with asymptomatic restenosis exceeds $10,000. Similarly, the cost to identify a patient with asymptomatic restenosis increases when the proportion of patients with asymptomatic restenosis decreases. The cost, associated with the use of routine functional testing for the identification of asymptomatic patients with restenosis appears exorbitant. However, a formal study is warranted to determine the cost-efficacy of such a strategy. Cathet. Cardiovasc. Intervent. 48:352-356, 1999.

Value of exercise electrocardiography in the detection of restenosis after coronary angioplasty in patients with one-vessel disease

Exercise treadmill testing (ETT) is considered an unreliable method for detection of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The studies on which this belief is based have used quantitative coronary angiography (QCA) as a reference. The inherent limitations of angiography have been demonstrated by intravascular ultrasound (IVUS). To determine the value of ETT for detecting restenosis when IVUS criteria are used to define restenosis, we studied 29 patients with angiographically documented 1-vessel coronary disease (<35% stenosis in all nondilated segments) who underwent angioplasty. ETT was performed < or =2 weeks before follow-up angiography and IVUS imaging. Only patients without any abnormalities precluding an accurate reading of the ST segment during ETT were included. Restenosis was defined as a > or =50% diameter stenosis by QCA criteria and as a cross-sectional area narrowing of > or =75% by IVUS. The ETT was positive in 12 patients and restenosis was documented by QCA and IVUS in 38% and 48% of cases, respectively. Sensitivity, specificity, and positive and negative predictive values of ETT when QCA was used as a reference were 55%, 67%, 50%, and 71%, respectively. This corresponded to an accuracy of 62% when compared with QCA. Sensitivity, specificity, and positive and negative predictive values were 79%, 93%, 92%, and 82% when ETT was compared with IVUS, with an accuracy of 86% (p = 0.002). Thus, ETT is a reliable noninvasive method for detecting the presence of restenosis after PTCA in patients with 1-vessel coronary artery disease. The presence of > or =75% cross-sectional narrowing shown by IVUS is well correlated with > or =1-mm ST-segment depression at follow-up ETT after PTCA.