Differences of regional coronary flow reserve assessed by adenosine thallium-201 scintigraphy early and six months after successful percutaneous transluminal coronary angioplasty or stent implantation

Quantitative contrast stress echocardiography in assessment of restenosis after percutaneous coronary intervention in stable coronary artery disease

AIMS

Quantitative contrast stress echocardiography (CSE) can assess regional myocardial perfusion. The aim of this study was to evaluate the performance of quantitative CSE in the detection of restenosis after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Thirty-three patients with stable coronary artery disease, scheduled for PCI, underwent CSE and quantitative coronary angiography (QCA) before and 9 months after PCI. Regional myocardial perfusion was analysed blinded to QCA results. QCA identified 38 significant stenoses (> or =50% diameter reduction). Before PCI, perfusion during stress was significantly reduced in regions supplied by stenotic arteries; blood flow velocity (Deltabeta) -3.9 (-9.0 to 0.5) s(-1), perfusion rate (DeltaA x beta) -175.0 (-518.0 to 58.5) s(-1), and refilling time (Deltart) 210 (-22 to 452)ms, compared with the perfusion increase seen in regions supplied by non-stenotic arteries; Deltabeta 1.6 (-0.7 to 4.4) s(-1), DeltaA x beta 151.7 (-67.0 to 300.5) s(-1), and Deltart -47 (-195 to 89) ms, all P < 0.05. At follow-up, regional stress-induced perfusion improved in 29 regions with successful PCI; Deltabeta 0.1 (-2.7 to 3.6), DeltaA x beta 30.5 (-133.3 to 232.1), and Deltart -99 (-247 to 125), all P < or = 0.01, although there was no improvement in nine regions with restenosis; Deltabeta 0.9 (-1.5 to 5.3), DeltaAxbeta 65.7 (-40.8 to 412.6), and Deltart -79 (-268 to 163), P = NS.

CONCLUSION

Quantitative CSE has the potential to detect angiographically significant coronary artery stenoses as well as angiographic success after PCI.

Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

PURPOSE

If coronary artery was treated with optimal stent implantation, myocardial perfusion in the territory supplied by a dilated coronary artery should be not reversible. However, several studies have demonstrated reversible perfusion in the territory supplied by a coronary artery with an optimally implanted stent. The main objective of this study was to evaluate the incidence of reversible defects detected by M-SPECT early after optimal PTCA with stent implantation. Its second objective was to determine the predictive value of detecting reversible defects after stent implantation for late restenosis.

METHODS

About 66 patients that underwent M-SPECT within 24 h of successful PTCA with stent implantation were included. All patients were followed up clinically and angiographically. The incidence of reversible perfusion defects on M-SPECT and the rate of late restenosis in target coronary arteries were evaluated retrospectively.

RESULTS

Reversible perfusion defects on M-SPECT were observed in 26% of the patients and in 36% of lesions following successful PTCA with stent implantation. The incidence of late restenosis was significantly higher in patients and lesions with reversible perfusion defects (47% vs. 18%). According to binary logistic regression analysis, the presence of a reversible perfusion defects was the only independent predictor of late restenosis.

Contrast-enhanced MR Imaging for Evaluation of Coronary Artery Disease before Elective Repair of Aortic Aneurysm

PURPOSE

To prospectively evaluate the accuracy of first-pass contrast material-enhanced magnetic resonance (MR) imaging during stress and delayed contrast-enhanced MR imaging in the detection of significant coronary artery disease in patients before elective repair of aortic aneurysm.

MATERIALS AND METHODS

The study was approved by the institutional ethics committee, and informed consent was obtained from all patients. MR imaging was performed in 49 patients (42 men and seven women; mean age, 72.2 years; age range, 58-85 years) before the elective repair of atherosclerotic aortic aneurysms. Thirty-two patients had an abdominal aneurysm, 12 had a thoracic aneurysm, and five had a thoracoabdominal aneurysm. First-pass contrast-enhanced MR images were obtained with short-axis sections encompassing the entire left ventricular myocardium in the resting state and during pharmacologic stress. Inversion-recovery-prepared delayed contrast-enhanced MR images were obtained with breath holding to evaluate for the presence of infarction. All patients underwent coronary angiography within 2 weeks of MR imaging, and these findings were used as the standard of reference. The diagnostic results of first-pass contrast-enhanced MR imaging, delayed contrast-enhanced MR imaging, and a combination of both MR imaging methods in the detection of significant coronary artery disease were expressed as sensitivity, specificity, and accuracy.

RESULTS

Coronary angiography depicted a clinically significant stenosis (>70% luminal diameter narrowing) in the coronary artery in 34 of the 49 patients (69%). First-pass contrast-enhanced MR imaging depicted stress-induced hypoenhancement in 27 of those 34 patients (79%). Delayed myocardial enhancement was observed in 17 of the 34 patients (50%). The overall sensitivity of rest-stress first-pass contrast-enhanced MR imaging and delayed contrast-enhanced MR imaging combined in the prediction of at least one coronary artery with significant stenosis was 88% (30 of 34 patients). The specificity and accuracy of MR imaging were 87% (13 of 15 patients) and 88% (43 of 49 patients), respectively.

CONCLUSION

Contrast-enhanced MR imaging had an accuracy of 88% in the detection of significant coronary artery disease in patients with aortic aneurysm.

Diagnostic accuracy of stress first-pass contrast-enhanced myocardial perfusion MRI compared with stress myocardial perfusion scintigraphy

OBJECTIVE

The purpose of this study was to determine the diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery prepared turbo fast low-angle shot (turbo FLASH) compared with stress myocardial perfusion scintigraphy. Recent studies show that first-pass contrast-enhanced myocardial perfusion MRI can provide noninvasive detection of low-limiting stenosis in the coronary artery.

MATERIALS AND METHODS

First-pass contrast-enhanced MR images were acquired at rest and during stress in 40 patients with suspected coronary artery disease. All patients underwent thallium-201 SPECT without attenuation correction and coronary angiography. Two reviewers independently assigned one of five confidence grades without knowing the results of coronary angiography for receiver operating characteristic (ROC) analysis. Luminal stenosis >70% on coronary angiography was used as a reference standard.

RESULTS

On coronary angiography, 70% or greater diameter stenosis of the coronary artery was observed in 21 (52.5%) of 40 patients. The areas under the ROC curve for detection of significant stenosis in the individual coronary artery were 0.86 (observer 1) and 0.84 (observer 2) for MRI. These values were 0.79 (observer 1, p = not significant) and 0.72 (observer 2, p = not significant) for 201Tl SPECT.

CONCLUSION

The diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery-prepared turbo FLASH was comparable with that of stress 201Tl SPECT. Stress first-pass contrast-enhanced MRI is a noninvasive technique that can be used as an alternative to stress myocardial perfusion scintigraphy.

Myocardial perfusion after angioplasty in patients suspected of having single-vessel coronary artery disease: improvement detected at rest-stress first-pass perfusion MR imaging--initial experience

PURPOSE

To prospectively assess myocardial perfusion before and after successful intervention in patients suspected of having single-vessel coronary artery disease by using a steady-state free precession (SSFP) perfusion magnetic resonance (MR) imaging sequence.

MATERIALS AND METHODS

Local ethics committee approval and informed consent were obtained. Rest-stress perfusion MR imaging studies were performed in 18 patients with coronary artery disease (12 men, six women; mean age, 58.6 years +/- 13.6 [standard deviation]; range, 30-79 years) at 1.5 T with a multisection saturation-recovery SSFP sequence and 0.025 mmol gadopentetate dimeglumine per kilogram of body weight. MR studies were performed before (n = 18), several days after (n = 18), and 8 months after (n = 10) coronary intervention. Nine patients underwent percutaneous transluminal coronary angioplasty (PTCA) alone, and nine patients underwent PTCA with stent placement. Myocardial perfusion reserve index (MPRI) was calculated by dividing results of myocardial perfusion at maximal vasodilation by results at rest. The standard for myocardial perfusion was technetium 99m tetrofosmin single photon emission computed tomography. Statistical significance was tested with univariate variance analysis and Student t tests.

RESULTS

In the area of the stenosed vessel, MPRI was 1.04 +/- 0.24 before treatment and 2.18 +/- 0.57 several days afterward (P < .001). In remote areas, MPRI was 2.42 +/- 0.44. In the stent group, MPRI increased by 156%, from 0.99 +/- 0.20 before stent placement to 2.53 +/- 0.53 after (P < .001). Similarly, in the PTCA only group, MPRI increased by 72%, from 1.08 +/- 0.27 before PTCA to 1.87 +/- 0.39 after (P < .001). At follow-up in patients without recurring chest pain, MPRI was 2.14 +/- 0.37 in the area of the treated artery and 2.29 +/- 0.47 in remote areas (P = .06).

CONCLUSION

The MPRI, derived from rest-stress examinations, can provide information on success of interventional procedures in stenosed coronary arteries.

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.

Noninfarcted myocardium: correlation between dynamic first-pass contrast-enhanced myocardial MR imaging and quantitative coronary angiography

PURPOSE

To determine the accuracy of first-pass contrast material-enhanced stress myocardial magnetic resonance (MR) imaging for depiction of myocardial ischemia in patients without myocardial infarction.

MATERIALS AND METHODS

First-pass contrast-enhanced MR images of the entire left ventricle were acquired in 104 patients at rest and during dipyridamole-induced stress by using an interleaved notched saturation technique. Coronary angiography was performed in all patients, and stress perfusion single photon emission computed tomography (SPECT) was performed in 69 patients. Receiver operating characteristic curve analysis was performed to compare the diagnostic accuracies of first-pass contrast-enhanced stress MR imaging and stress SPECT, with coronary angiography as the reference standard.

RESULTS

The overall sensitivity of MR imaging for depicting at least one coronary artery with significant stenosis was 90% (69 of 77 patients). The sensitivities of MR imaging for depiction of single-, double-, and triple-vessel stenoses were 85% (33 of 39 patients), 96% (22 of 23 patients), and 100% (15 of 15 patients), respectively. The specificity of MR imaging for identification of patients with significant coronary artery stenoses was 85% (23 of 27 patients). The areas under the receiver operating characteristic curve for detection of significant stenosis in individual coronary arteries were 0.888 (observer 1) and 0.911 (observer 2) for MR imaging and 0.707 (observer 1, P <.001) and 0.750 (observer 2, P <.001) for SPECT.

CONCLUSION

In patients without myocardial infarction, stress enhancement at dynamic MR imaging correlates more closely with quantitative coronary angiography results than does stress enhancement at SPECT.

Predictive value of myocardial tomoscintigraphy in asymptomatic diabetic patients after percutaneous coronary intervention

OBJECTIVE

This study was designed to assess the prognostic value of myocardial tomoscintigraphy perfusion imaging after percutaneous coronary intervention (PCI) in asymptomatic diabetic patients.

METHODS

One hundred and fourteen diabetic patients were followed up during 27+/-16 (mean+/-SD) months after the myocardial tomoscintigraphy. PCI-related events were studied after myocardial tomoscintigraphy stress testing and included major cardiac events (MACE) (cardiovascular death, myocardial infarction) and revascularization (bypass surgery or new PCI). Stress myocardial tomoscintigraphy imaging was performed 5+/-5 months after PCI and ischemia was considered as present if at least 2 contiguous segments were showing reversible defects.

RESULTS

Persistent silent ischemia was found in 49/114 (43%) patients. No difference was observed between the two groups for MACE: four among the 65 (6%) non ischemic patients versus 2 among the 49 (4%) ischemic patients (NS). In contrast, 15 (31%) among the ischemic patients and 4 (6%) among the non ischemic patients underwent iterative revascularization (p<0.01). The relative risk of revascularization for patients with significant ischemia was 5.5 versus non ischemic patients (p<0.001).

CONCLUSION

After PCI, in asymptomatic diabetic patients followed by myocardial tomoscintigraphy a high frequency of persistent silent ischemia was found and associated with a high risk for repeat interventional procedure, although no increase in major cardiac events was observed.

Restoration of myocardial blood flow following percutaneous coronary balloon dilatation and stent implantation: assessment with qualitative and quantitative contrast-enhanced magnetic resonance imaging

AIM

To examine the serial use of magnetic resonance imaging (MRI) to evaluate regional myocardial perfusion changes following percutaneous coronary angioplasty and stent implantation (PTCA).

MATERIALS AND METHODS

Six patients with single vessel coronary artery disease (CAD) underwent contrast-enhanced first pass MRI immediately prior to (visit A) and within 7 days after (visit B) PTCA. Three sequential short axis slices were obtained after gadodiamide (Gd) bolus (0.025 mmol/kg(-1)) at rest and during adenosine. Each short axis was divided radially into eight regions of interest (ROIs). ROIs were anatomically assigned to a coronary artery territory (CAT). Stress and rest qualitative and quantitative (unidirectional extraction fraction constant (K(i)); index of myocardial perfusion reserve (MPRI) = stressK(i) / restK(i)) perfusion parameters were determined for ROI supplied by remote and stenosed/stented vessels for each visit.

RESULTS

In stented ROIs the number of ROIs demonstrating normal perfusion, as opposed to reversible perfusion deficits, increased. Qualitative perfusion assessment in remote CATs was unchanged. MPRI in stenotic CATs was lower than in remote CATs at visit A (P < 0.001). Following PTCA, MPRI increased in stented CATs (P < 0.001) but was unchanged in remote CATs.

CONCLUSION

Restoration of myocardial perfusion following PTCA can be delineated with qualitative and quantitative perfusion MRI. Although at present the investigation is technically complex and not perfectly sensitive or specific, MRI has the potential to be a valuable tool for patient follow-up and evaluation of revascularization strategy efficacy.

Long-term prognostic value of 201Tl single-photon emission computed tomographic myocardial perfusion imaging after coronary stenting

BACKGROUND

The prognostic value of (201)Tl myocardial imaging has been demonstrated in several studies concerning patients with a known significant coronary artery disease. However, the evolution of a coronary stenosis after stenting is difficult to predict. This study was designed to assess the prognostic value of (201)Tl single-photon emission computed tomography (thallium SPECT) perfusion imaging in patients after intracoronary stenting.

METHODS

One hundred fifty-two patients were studied. They were followed up during 40 +/- 13 (mean +/- SD) months after thallium SPECT. Stent-related events were studied after thallium stress testing and included cardiovascular death, myocardial infarction, and revascularization. Stress thallium imaging was performed 5 +/- 2 months after stenting, and ischemia was considered to be present if at least 2 contiguous segments were showing reversible defects.

RESULTS

Only 3 (3%) among the 105 nonischemic patients had major cardiac events during the follow-up versus 13 (28%) of the 47 ischemic patients (P < .001) after thallium SPECT. The relative risk of major cardiac events for patients with significant ischemia was 10.5 compared with nonischemic patients (P < .001). Fourteen (30%) of the ischemic patients and 8 (8%) among the nonischemic patients underwent iterative revascularization (P < .001). Therefore, only 11 (10%) of the nonischemic patients had major cardiac events or revascularization compared with 24 (51%) of the ischemic patients (P < .001).

CONCLUSIONS

Absence of ischemia on thallium SPECT imaging at 5 months after coronary stenting indicates a low risk for cardiovascular events or interventional procedure. These results may have important clinical implications in patient treatment.

Improvement of myocardial perfusion reserve early after coronary intervention: assessment with cardiac magnetic resonance imaging

OBJECTIVES

The purpose of this study was to determine the potential value of magnetic resonance myocardial perfusion in the follow-up of patients after coronary intervention.

BACKGROUND

In some patients a residual impairment of myocardial perfusion reserve (MPR) early after successful coronary intervention has been observed. In this study we evaluated an MPR index before and after intervention with magnetic resonance.

METHODS

Thirty-five patients with single- and multivessel coronary artery disease were studied before and 24 h after intervention. The signal intensity time curves of the first pass of a gadolinium-diethylene triamine pentacetic acid bolus injected via a central vein catheter were evaluated before and after dipyridamole infusion. The upslope was determined using a linear fit. Myocardial perfusion reserve index was estimated from the alterations of the upslope.

RESULTS

The MPR index in segments perfused by the stenotic artery was significantly lower than in the control segments (1.07 +/- 0.24 vs. 2.18 +/- 0.35, p < 0.001) and improved significantly after intervention (1.89 +/- 0.39, p < 0.001) but did not normalize completely (p < 0.01). After intervention the MPR index remained significantly lower in the balloon percutaneous transluminal coronary angioplasty group (1.72 +/- 0.38; n = 13) in comparison with the stent group (1.99 +/- 0.36, n = 18, p < 0.05). In the stent group a complete normalization of the MPR index was found 24 h after stenting.

CONCLUSIONS

Magnetic resonance perfusion measurements allow a reliable assessment of MPR index. An improvement of MPR index can be observed after coronary intervention, which is more pronounced after stenting. Magnetic resonance perfusion measurements allow the assessment and may be useful for the follow-up of patients with coronary artery disease after coronary intervention.

Coronary flow reserve early and late after minimally invasive coronary artery bypass grafting in patients with totally occluded left anterior descending coronary artery

BACKGROUND

The impairment of flow reserve of the left anterior descending coronary artery in the early postoperative period in patients receiving a left internal thoracic artery graft has been related to the effects of cardiopulmonary bypass. Indeed, the late improvement in flow has been attributed to a late increase in left internal thoracic artery diameter.

METHODS

We evaluated 12 patients who underwent minimally invasive direct coronary artery bypass surgery with the internal thoracic artery used to graft an occluded left anterior descending artery without extracorporeal circulation. Early and 6 months after the operation, patients underwent a second angiogram of the left internal thoracic artery graft and assessment of coronary flow reserve by use of an intracoronary 0.014-inch Doppler guide wire.

RESULTS

At the late study, coronary flow reserve had increased compared with the early postoperative data from 1.8 +/- 0.4 (standard deviation) to 2.5 +/- 0.6 (P =.002) because of a significant decrease in baseline averaged peak velocity (32.4 +/- 6.2 vs 21.3 +/- 6.4 cm/s, P =.002), whereas the hyperemic values were similar (51 +/- 6 vs 53.7 +/- 21.9 cm/s, P =.6). The diameters of the thoracic artery (2.1 +/- 0.3 vs 2.2 +/- 0.3 mm, P =. 7) and the left anterior descending coronary artery (1.8 +/- 0.1 vs 1.8 +/- 0.2 mm, P =.5), as well as myocardial oxygen consumption (106 +/- 14 vs 101 +/- 16 mm Hg. beats/min. 10(-2), P =.5), were unchanged.

CONCLUSIONS

Our findings suggest that the late improvement in coronary flow reserve is independent of the diameter of the graft and probably reflects an early distal coronary vessel dysfunction, which normalizes with time.

Primary stenting in acute myocardial infarction: influence of diabetes mellitus in angiographic results and clinical outcome

BACKGROUND

The outcome of patients with diabetes after myocardial infarction (MI) has traditionally been worse than in their nondiabetic counterparts before and during the thrombolytic therapy era. Whether the fate of patients with diabetes might improve with mechanical intervention, particularly with primary stenting, has not previously been studied.

METHODS

We compared the angiographic and clinical outcome of 76 nondiabetic patients (aged 61 +/- 14 years; 66% male) and 28 patients with diabetes (aged 65 +/- 12 years; 64% male) consecutively treated with primary stenting for acute MI. Coronary Thrombolysis In Myocardial Infarction grade 3 flow was restored in 96% of diabetic and 97% of nondiabetic patients.

RESULTS

Angiographic results after stent deployment were similar in the 2 groups. At 1-month follow-up, all patients in both groups were alive. Patients with diabetes had a much higher incidence of stent thrombosis (18% vs 1%; P =.003), which accounted for the majority of the major cardiac events at 1 month (21% vs 4%; P =.009). At a mean follow-up of 315 +/- 13 days, 99% of nondiabetic and 89% of patients with diabetes were alive (P =.04). Overall freedom from a major cardiac event (death, MI, target vessel revascularization) at 315 +/- 13 day follow-up was 88% for nondiabetics and 54% for patients with diabetes (P =.0003). By multivariate analysis, diabetes mellitus was the most important predictor for development of 1-month (RR 9.89; 95% confidence interval, 1.6-30) and late major cardiovascular events (RR 8.39; 95% confidence interval, 2.93-24).

CONCLUSIONS

Primary stenting in acute MI is highly effective in restoring immediate TIMI 3 coronary flow in nondiabetic patients and patients with diabetes. This procedure may improve benefit in terms of mortality rate to both groups, particularly in patients with diabetes, compared with previous reports with thrombolytic therapy. Nevertheless, stent thrombosis and major cardiovascular events at 1 month and late follow-up are more frequent in patients with diabetes.