Changes in coronary endothelial function predict progression of allograft vasculopathy after heart transplantation.

OBJECTIVE: Coronary endothelial dysfunction may be an early marker for cardiac allograft vasculopathy (CAV) in orthotopic heart transplant recipients. We used serial studies to evaluate changes in coronary endothelial function in patients with and without clinically evident CAV. BACKGROUND: In serial studies with intravascular ultrasound (IVUS) and Doppler flow wire measurements, we previously demonstrated that annual decrements in coronary endothelial function are associated with progressive intimal thickening. METHODS: We studied 45 patients annually, beginning at transplantation until pre-specified end-points (angiographic CAV or cardiac death) were reached. At each study, we measured coronary endothelial function using intracoronary infusions of adenosine, acetylcholine, and nitroglycerin. We simultaneously recorded IVUS images and Doppler velocities. RESULTS: Of the 45 patients studied, 9 reached end-points during the study (6 had CAV and 3 died). The mean annual change in area response to acetylcholine was -4.5% +/- 3.0% in patients who reached end-points and -0.9% +/- 1.5% in those who did not (p = 0.04). The mean annual decrement in flow response to acetylcholine was greater in patients who reached end-points (-31% +/- 11% vs -5% +/- 5%, p = 0.08). Responses to adenosine and nitroglycerin did not differ. CONCLUSIONS: When serial responses were evaluated, patients with end-points had more rapid decreases in endothelial function. The rate of disease progression may be more important than the absolute degree of intimal thickening in early CAV. These data implicate endothelial dysfunction in the development of clinically significant vasculopathy and suggest that serial studies of endothelial function may provide important prognostic information about the development of CAV after heart transplantation.

Use of corticosteroids in the treatment of cholesterol crystal embolization after percutaneous transluminal coronary angioplasty and stent placement.

Cholesterol crystal embolization is a rare but recognized complication of cardiac catheterization. While management has traditionally been supportive only, we demonstrate the successful use of corticosteroids in treatment of a patient with cholesterol crystal embolization to the distal extremity.

The impact of adjunctive adenosine infusion during exercise myocardial perfusion imaging: Results of the Both Exercise and Adenosine Stress Test (BEAST) trial.

BACKGROUND: Failure to achieve an adequate heart rate limits the sensitivity of exercise myocardial perfusion imaging (MPI) for the detection of coronary artery disease. In addition, it is often not possible to discontinue medications that may blunt the heart rate response to exercise, because of conditions such as hypertension or angina. However, if pharmacologic stress testing is performed, the ability to assess functional capacity is lost. Accordingly, we developed a protocol that incorporates adenosine stress with symptom-limited exercise. METHODS AND RESULTS: As part of a multicenter study, 35 patients were enrolled prospectively and underwent both exercise MPI and exercise MPI with a 4-minute adenosine infusion on a separate day. Technetium 99m sestamibi was injected at or near peak exercise (exercise only) and at 2 minutes into the adenosine infusion (combined exercise and adenosine). The perfusion images were interpreted in a blinded fashion. The combined adenosine and exercise protocol was well tolerated. The summed stress scores and summed difference scores were greater in the exercise-plus-adenosine group than in the exercise-only group (10.0 vs 8.5, P =.02, and 4.9 vs 3.3, P =.002, respectively). Exercise time was slightly but significantly less with the exercise-plus-adenosine protocol (8 minutes 46 seconds vs 8 minutes 11 seconds, P =.027). CONCLUSION: A protocol combining 4 minutes of adenosine infusion with symptom-limited exercise was safe and well tolerated. Furthermore, this protocol resulted in a greater amount of myocardial ischemia detected on MPI while allowing for the assessment of functional capacity. A combined exercise and adenosine protocol may be a useful test for patients undergoing MPI who are unlikely to achieve an adequate chronotropic response.

Visual assessment of procedural results following treatment with Sr-90 beta-radiation for instent restenosis.

BACKGROUND: Visual assessment (VA) of postprocedural % diameter stenosis (DS) is used routinely in clinical practice to determine the adequacy of coronary intervention. Although VA has been shown to underestimate final %DS after balloon angioplasty compared to quantitative coronary angiography (QCA), the impact of this effect on clinical outcomes following treatment with intracoronary radiation therapy (IRT) with Sr-90 for instent restenosis (ISR) is unknown. METHODS: To determine the effect of VA on the rate of major adverse cardiac events (MACEs) after IRT for ISR, we compared the clinical outcomes of 102 consecutive patients based on postprocedural %DS by QCA vs. %DS by VA. MACE was defined as death, M1 or need for target vessel revascularization (TVR). RESULTS: MACE rates for the 102 consecutive patients grouped according to postprocedural %DS by QCA and VA were compared. The mean %DS by QCA was 30.7%, while the mean %DS by VA was 12.5%. The mean %DS by VA across the QCA subgroups were 13.67%, 10.71% and 13.37%, respectively (P = .244). Fifty-two patients (51.0%) had %DS > 30% by QCA with the highest MACE percentage occurring in this subgroup. CONCLUSION: VA underestimated the %DS compared to QCA, and it was associated with worse MACE following treatment with Sr-90 for ISR.