Coronary microvascular dysfunction correlates with the new onset of cardiac allograft vasculopathy in heart transplant patients with normal coronary angiography.

Coronary microvascular dysfunction is emerging as a strong predictor of outcome in heart transplantation (HT). We assessed the validity of microvascular dysfunction, defined by means of a reduced coronary flow reserve (CFR), as a factor associated with new onset epicardial cardiac allograft vasculopathy (CAV) or death. We studied 105 patients at 4 ± 1 years post-HT with a normal coronary angiography (CA). New onset CAV was assessed by CA. CFR was assessed in the left anterior descending (LAD) coronary artery by transthoracic Doppler echocardiography and calculated as the ratio of hyperaemic to basal blood flow velocity. A CFR ≤ 2.5 was considered abnormal. Epicardial CAV onset or death was assessed during a follow-up of 10 years. New onset CAV was diagnosed in 30 patients (28.6%) (Group A), and the CA was normal in the remaining 75 patients (71.4%) (Group B). Group A had reduced CFR compared with group B (2.4 ± 0.6 vs. 3.2 ± 0.7, p < 0.0001). A CFR ≤ 2.5 was independently associated with a higher probability of new onset CAV (p < 0.0001) and a higher probability of death, regardless of CAV onset (p < 0.01). Microvascular dysfunction is independently associated with the onset of epicardial CAV, and associated with a higher risk of death, regardless of CAV onset.

Lewis histo-blood group system phenotyping and genotyping reveal divergence in the association of Le(a-b-) phenotype and type 1 diabetes.

BACKGROUND AND OBJECTIVES: The red blood cell Le(a-b-) phenotype was proposed as risk factor for type 1 diabetes, but contradictory results were published elsewhere. This study re-examined the potential association between Lewis histo-blood group system and type 1 diabetes. MATERIAL AND METHODS: Patients and controls of both sexes, Caucasians and non-Caucasians, matched by sex, geographical origin and ethnicity were evaluated. The red blood cell Lewis phenotypes were identified by gel column agglutination and also inferred from the FUT2 and FUT3 genotyping. RESULTS: The Le(a-b-) phenotype was prevalent in patients with type 1 diabetes, and the Le(a-b+) phenotype was prevalent in controls when both were determined by gel columns agglutination. No differences were observed in the frequencies of the Le(a-b-) phenotype inferred from the FUT2 and FUT3 genotyping between patients and controls. CONCLUSIONS: The Lewis red blood cell phenotyping and genotyping reveal divergence in the association of Le(a-b-) phenotype and type 1 diabetes.

Everolimus prevents coronary microvasculopathy in heart transplant recipients with normal coronary angiograms: an anatomo-functional study.

BACKGROUND: Coronary allograft vasculopathy (CAV) involves both epicardial vessels and coronary microcirculation. Little is known about the effect of everolimus on coronary microvasculopathy in heart transplantation (HT). The aim of our study was to assess the pathological substrate of coronary flow reserve (CFR) impairment in HT patients and the effect of everolimus on microvascular remodeling and CFR. METHODS: We studied 28 HT patients with normal coronary angiograms (25 male, age at HT 54±10 years). Immunosuppressive regimen consisted of cyclosporine and everolimus (10 patients) or mycophenolate mophetil (18 patients). They were evaluated with digital microscopy for morphometric analysis of fibrosis and microvascular remodeling. Coronary flow velocity in the left anterior descending coronary artery was detected using transthoracic Doppler echocardiography at rest and during adenosine infusion. CFR was the ratio of hyperaemic diastolic flow velocity (DFV) to resting DFV. A CFR≤2.5 was considered abnormal and sign of coronary microvascular dysfunction. RESULTS: In patients with CFR≤2.5 the thickness of the tunica media of intramyocardial arterioles was greater than in patients with CFR>2.5 (39±2 vs 17±3 µm; P=.02). Microvascular remodeling was significantly higher in patients with CFR≤2.5 (72.7±2.4 vs 50.4±8.4%; P<.007). Capillary density and fibrosis were comparable between groups (157.2±42.4 vs 175.7±42.4 capillaries/mm2; P=.3; and 6.8±5 vs 8.3±4.9%; P=.4, respectively). The thickness of the tunica media of intramyocardial arterioles was lower in patients whose therapy included everolimus (15±2 vs 32±4 µm, P=.03) and CFR was higher (3.2±0.5 vs 2.8±0.9; P=.03). CONCLUSION: The pathological substrate of reduced CFR in HT patients seems to be a hypertrophic remodeling of coronary arterioles. Everolimus appears to prevent such microvascular remodeling and preserve coronary flow reserve.