Evaluation of contrast wash-in and peak enhancement in adenosine first pass perfusion CMR in patients post bypass surgery.

BACKGROUND: Adenosine first pass perfusion cardiovascular magnetic resonance (CMR) yields excellent results for the detection of significant coronary artery disease (CAD). In patients with coronary artery bypass grafts (CABG) the kinetics of a contrast bolus may by altered only due to different distances through the bypass grafts compared to native vessels, thereby possibly imitating a perfusion defect. The aim of the study was to evaluate semiquantitative perfusion parameters in order to assess possible differences in epicardial contrast kinetics in areas supplied by native coronaries and CABG, both without significant stenosis. METHODS: Twenty patients with invasive exclusion of significant CAD (control group) and 38 patients with CABG without angiographically significant (>or=50%) stenosis in unbypassed coronaries or grafts were retrospectively included in the study. They underwent adenosine first pass (0.05 mmol/kg Gd-DTPA) perfusion (3 short axis views/heart beat) and late gadolinium enhancement (LGE) imaging 1 day before invasive coronary angiography. Areas perfused by native coronaries and/or the different bypasses were identified in X-ray angiography using the 16 segment model. In each of these areas upslope and maximal signal intensity (SImax) relative to the left ventricular parameters, time to 50% maximal signal intensity (TSI50%max) and time to maximal signal intensity (TSImax) were calculated. RESULTS: In areas perfused by coronary arteries with bypasses compared to native coronaries relative upslope and relative SImax did not show a significant difference. TSI50%max and TSImax in native coronaries and bypasses were 7.2s +/- 1.9s vs. 7.5s +/- 1.9s (p < 0.05) and 12.6s +/- 3.0s vs. 13.1s +/- 3.0s (p < 0.05), respectively. The delay in Tmax resulted in a significant (p < 0.05) delay of 0.5 +/- 1.1 heart beats (=images) when adjusted to the heart rate. Differences in time were most pronounced in areas perfused by left internal mammary artery grafts rather than by venous CABG, but were also present between native vessel territories in patients without CAD, albeit with smaller variability. CONCLUSION: Adenosine perfusion CMR in patients post CABG may be associated with a short delay in contrast arrival. However, once the contrast is in the myocardium there is similar wash-in kinetics and peak enhancement. Therefore, since the delay is only short, the possibly differing contrast kinetics through grafts and native vessels does not seem to be a limiting factor for the accuracy of first pass adenosine perfusion in patients post CABG.

Intravascular ultrasound assessment of longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease after heart transplantation.

AIMS: The purpose of this three-dimensional intracoronary ultrasound (ICUS) study was to assess longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease (CAD) after heart transplantation (HTX). METHODS AND RESULTS: Out of 334 patients without diameter stenosis >/=25% determined by coronary angiography, 321 underwent successful three-dimensional ICUS (30 MHz) of the left main coronary artery (LMCA) and all segments of the left anterior descending coronary artery (LAD). Early plaque formation was found in 296 patients (92.2%). Single (focal CAD, n = 65) or multiple (polyfocal CAD, n = 77), discrete coronary lesions were found in 142 patients and continuous plaque formation of at least one entire coronary segment (diffuse CAD) in 154 patients. Using multivariate regression analysis, male sex (P = 0.01), increasing post-transplantation time (P = 0.003) and increasing donor age (P = 0.001) were independent clinical predictors for diffuse CAD. Both focal and diffuse CAD most frequently affected the proximal LAD (88% compared with 89.6%, NS). The mean intimal index of each LAD segment was significantly higher in patients with diffuse CAD (P < 0.001) and showed a proximal-to-distal decline in patients with focal/polyfocal (LMCA, 10.1 +/- 14.3, LAD-6, 30.1 +/- 17.4%, LAD-7, 16.3 +/- 14.1%, LAD-8, 4.6 +/- 11.1%; P < 0.001) and diffuse (LMCA, 27.0 +/- 16.0, LAD-6, 47.8 +/- 16.1%, LAD-7, 41.9 +/- 14.5%, LAD-8, 24.9 +/- 23.3%; P < 0.01) CAD. CONCLUSION: Evaluation of longitudinal plaque distribution after HTX by three-dimensional ICUS revealed a time-dependent increase in the incidence of diffuse CAD and a proximal-to-distal decline in frequency and magnitude of early plaque formation.

Magnetic resonance adenosine perfusion imaging in patients after coronary artery bypass graft surgery.

OBJECTIVES: The aim of the study was to evaluate the feasibility and diagnostic performance of the combination of adenosine stress perfusion and late gadolinium enhancement (LGE) in patients after coronary artery bypass graft surgery (CABG). BACKGROUND: Cardiac magnetic resonance (CMR) imaging allows the detection of significant coronary artery disease by adenosine stress perfusion and infarct imaging. Myocardial contrast kinetics may be altered in patients after CABG owing to more complex myocardial perfusion and different distances of the contrast bolus through different bypasses and native coronary vessels. Additionally, all studies have excluded patients after CABG. METHODS: In all, 78 patients (age 66 +/- 8 years; 71 men) underwent CMR imaging including left ventricular function, first-pass adenosine stress perfusion (adenosine 140 microg/min/kg) using 0.05 mmol/kg body weight gadolinium-diethylenetriaminepenta-acetic acid and an additional 0.15 mmol/kg for LGE 1 day before invasive coronary angiography. Images were analyzed visually using the speed of contrast wash-in and maximal signal intensity. Transmural LGE defects of the size of a vessel or graft territory defined by angiography were considered true negatives, even when supplied by a stenosed/occluded vessel/graft. Stenoses >50% in grafts and grafted or ungrafted native vessels (diameter > or =2 mm) in invasive angiography were considered significant. RESULTS: The prevalence of patients with significant stenosis was 63% (69% functionally 1-vessel, 28% 2-vessel, and 3% 3-vessel disease). Sensitivity and specificity were 77% and 90%, respectively, on a patient basis, and 71% and 89% on a vessel territory basis. Sensitivity, if only areas supplied by grafts (n = 196) were evaluated, was 78% and specificity was 94%, compared with territories supplied by ungrafted native vessels (n = 51) with sensitivity and specificity of 63% and 91%, respectively. Sensitivity and specificity for the 53 areas with prior infarction were 88% and 79%, respectively. CONCLUSIONS: For patients after surgical revascularization, the combination of stress perfusion and LGE yields good diagnostic accuracy for the detection and localization of significant stenoses. However, sensitivity is reduced compared with published data in patients without CABG. Prior myocardial infarction can be examined without loss of accuracy.

A decade of percutaneous coronary interventions in cardiac transplant recipients: a monocentric study in 160 patients.

BACKGROUND: Transplant vasculopathy is a long-term complication of cardiac transplantation. Percutaneous transluminal coronary angioplasty (PCI) is a method of choice for local revascularization that is also increasingly used in heart transplant patients. METHODS: Between October 1989 and November 2006, 160 adult cardiac transplant recipients (19 women) with mean age at heart transplantation of 47 +/- 12 years underwent PCI in 502 coronary segments during 319 catheterizations (balloon only, 209; bare metal stents, 227, drug-eluting stents, 66). Concomitant medical therapy, procedural data, primary success, recurrence of stenosis, and cardiac events (cardiac death or repeat transplantation) were analyzed retrospectively. Multivariate Cox proportional hazards analysis was performed. RESULTS: Stents reduced early and mid-term recurrence of stenosis but had no impact on graft survival. Drug-eluting stents did not improve the restenosis rate. Immunosuppression with mycophenolate mofetil and concomitant treatment with statins and clopidogrel were significantly associated with reduced recurrence of stenosis and prolonged graft survival. Low steroid dosage was associated with a positive impact on graft survival. CONCLUSIONS: Stenting in heart transplant patients has no impact on graft survival despite high primary success and deferred recurrence of stenosis. Early reduction of steroids, immunosuppression by mycophenolate mofetil, and concomitant treatment with statins are likely to reduce recurrent stenosis and to improve graft survival in heart transplant patients needing PCI. Long-term treatment with clopidogrel deserves further assessment.