Cardiac allograft vasculopathy after heart transplantation: electrocardiographically gated cardiac CT angiography for assessment.

PURPOSE: To evaluate the diagnostic accuracy of cardiac computed tomographic (CT) angiography without the use of ß-blockers compared with that of invasive angiography for the detection of cardiac allograft vasculopathy (CAV) in heart transplant recipients. MATERIALS AND METHODS: The study was approved by the research ethics committee and informed consent was obtained. Heart transplant recipients (n = 138) scheduled for routine invasive angiography were prospectively enrolled to undergo CT to evaluate coronary artery calcification and retrospectively gated cardiac CT angiography with a 64-section scanner. The cardiac CT angiographic images were systematically analyzed for image quality. Degree of CAV was assessed by using a 15-coronary segments model. The area under the receiver operating characteristic curve, sensitivity, specificity, and negative and positive predictive values of cardiac CT angiography for detection of CAV with any degree of stenosis and greater than or equal to 50% stenosis were calculated. RESULTS: Coronary artery calcification was absent in 82 patients, five (6%) of whom had CAV with 50% or more stenosis. Interpretable image quality was obtained in 130 (96%) of the 136 patients who completed the study and 1900 (98%) of 1948 segments. At the patient level, cardiac CT angiography had an area under the receiver operating characteristic curve, sensitivity, specificity, and positive and negative predictive values of 0.880 (95% confidence interval: 0.819, 0.941), 98%, 78%, 77%, and 98%, respectively, for diagnosis of CAV with any degree of stenosis, but for CAV with 50% or more stenosis, the corresponding values were 0.942 (95% confidence interval: 0.885, 1.000), 96%, 93%, 72%, and 99%, respectively. None of the 61 patients with normal cardiac CT angiographic results had CAV on the basis of invasive angiographic images. CONCLUSION: The study results show that cardiac CT angiography compares favorably with invasive angiography in detecting CAV in heart transplant recipients and may be a preferable screening technique because of its noninvasive nature. The absence of coronary artery calcification alone is not reliable enough for excluding CAV.

Brachial artery low-flow-mediated constriction is increased early after coronary intervention and reduces during recovery after acute coronary syndrome: characterization of a recently described index of vascular function.

AIMS: The endothelium plays a role in regulating vascular tone. Acute and dynamic changes in low-flow-mediated constriction (L-FMC) and how it changes with regard to traditional flow-mediated dilatation (FMD) have not been described. We aimed to investigate the changes in brachial artery L-FMC following percutaneous coronary intervention (PCI) and during recovery from non-ST-segment elevation myocardial infarction (NSTEMI). METHODS AND RESULTS: FMD was performed in accordance with a previously described technique in patients before and after PCI and in the recovery phase of NSTEMI, but in addition, L-FMC data were acquired from the last 30 s of cuff inflation. About 135 scans were performed in 96 participants (10 healthy volunteers and 86 patients). Measurement of brachial L-FMC was reproducible over hours. L-FMC was greater among patients with unstable vs. stable coronary atherosclerosis (-1.33 ±1.09% vs. -0.03 ± 1.26%, P < 0.01). Following PCI, FMD reduced (4.43 ± 2.93% vs. 1.66 ± 2.16%, P < 0.01) and L-FMC increased (-0.33 ± 0.76% vs. -1.63 ± 1.15%, P = 0.02). Furthermore, during convalescence from NSTEMI, L-FMC reduced (-1.37 ± 1.19% vs. 0.01 ± 0.82%, P = 0.02) in parallel with improvements in FMD (2.54 ± 2.19% vs. 5.15 ± 3.07%, P < 0.01). CONCLUSION: Brachial L-FMC can be measured reliably. Differences were observed between patients with stable and unstable coronary disease. L-FMC was acutely increased following PCI associated with reduced FMD and, in the recovery from NSTEMI, L-FMC reduced associated with increased FMD. These novel findings characterize acute and subacute variations in brachial L-FMC. The pathophysiological and clinical implications of these observations require further study.

Does myocardial perfusion scintigraphy predict improvement in symptoms and exercise capacity following successful elective percutaneous coronary intervention?

BACKGROUND: Elective percutaneous coronary intervention (PCI) without inducible ischaemia may not be beneficial. We investigated the prevalence of inducible hypoperfusion using myocardial perfusion scintigraphy (MPS) in patients undergoing PCI, and its ability to predict functional outcome. METHODS AND RESULTS: One hundred and twenty-three patients listed for elective PCI underwent MPS, using treadmill exercise where possible. Seventy-seven patients (63%) described chest pain in daily life. Seventy-four of 103 (72%) exercise ECG tests were positive. Ninety-one (74%) had inducible hypoperfusion on MPS (extensive in 25; 20%). Interventionalists were blinded to the scintigraphic results, and PCI was performed as planned. Six months later, Seattle Angina Questionnaire physical limitation score had improved from 66 to 76 (P < 0.0001), and peak treadmill workload from 7.2 +/- 2.3 to 9.0 +/- 2.7 METS (P < 0.0001). Sex, limiting chest pain on baseline exercise testing, and MPS summed difference score (SDS) were independent predictors of improvement. Patients with both limiting chest pain and SDS > or = 7 demonstrated an increase of 3.3 +/- 1.8 METS, compared with approximately 1.5 METS for other subgroups (P < 0.05). CONCLUSIONS: Many patients undergoing elective PCI in a UK centre have little or no evidence of inducible hypoperfusion. The combination of limiting chest pain during exercise testing and significant inducible hypoperfusion on MPS predicts a large increase in exercise capacity after PCI.

Low incidence and severity of transplant-associated coronary artery disease in heart transplants from live donors.

BACKGROUND: Hearts transplanted from patients undergoing heart-lung transplantation (domino hearts) are unique because they have not been subjected to the deleterious effects of brain-stem death. This study examines the incidence and severity of transplant-associated coronary artery disease in recipients of domino hearts. METHODS: We retrospectively reviewed angiographic and clinical data from 97 patients who survived more than 1 year after domino heart transplantation at our hospital. Duration of follow-up ranged from 1 to 11 years after transplantation. The diagnosis of coronary artery disease was based on angiographic criteria. RESULTS: At 1 year, freedom from angiographic coronary artery disease was 99% (70% confidence interval [CI], 97-100), at 5 years it was 83% (70% CI, 78-89), and at 10 years it was 77% (70% CI, 70-84). Donor age, cystic fibrosis in the donor, organ ischemia time during transplantation, and acute rejection after transplantation did not influence risk for the disease. We found an increased incidence of coronary disease in hearts from male donors compared with those from female donors: freedom from disease at 5 years was 72% (70% CI, 63-81) in men vs 93% (87-99) in women. Thirteen patients experienced coronary artery disease at a median of 3 years after transplantation; 4 patients died but most patients remained asymptomatic with angiographically mild disease at their last follow-up examination. CONCLUSIONS: We found decreased incidence and severity of transplant-associated coronary artery disease in recipients of domino hearts compared with that reported in recipients of cadaveric hearts. This data supports the continued practice of domino heart transplantation and also supports the hypothesis that brain death may contribute to the development of transplant coronary artery disease in recipients of hearts transplanted from cadaveric organ donors.

Regression of dilated-hypokinetic hypertrophic cardiomyopathy by biventricular cardiac pacing.

The evolution of hypertrophic cardiomyopathy (HCM) towards dilatation and hypokinesis is an increasingly recognized complication with a high incidence of adverse outcomes, including sudden cardiac death, requiring defibrillator implantation and cardiac transplantation. It is generally regarded as the irreversible 'burnt-out' end-stage manifestation of HCM. We report one of the first cases of profound regression of the dilated-hypokinetic state by the application of biventricular pacing and cardiac resynchronization therapy (CRT). Reviewing the literature on the role of pacing in HCM and the energetic rationale for CRT in HCM prompts us to suggest that further systematic studies are needed urgently to assess the role of CRT in HCM variants.