James F. Kenny

Differences in Myocardial Structure and Coronary Microvasculature Between Men and Women With Coronary Artery Disease

Women younger than 75 years with stable angina or acute coronary syndrome have higher cardiac mortality than similarly aged men, despite less obstructive coronary artery disease. To determine whether the myocardial structure and coronary microvasculature of women differs from that of men, we performed histological analysis of biopsies from nonischemic left ventricular myocardium from 46 men and 11 women undergoing coronary artery bypass graft surgery who did not have previous cardiac surgery, myocardial infarction, heart failure, atrial fibrillation, or furosemide therapy. The 2 patient groups had similar clinical characteristics, apart from a lower body surface area (BSA) in women (P=0.0015). Women had less interstitial fibrosis than men (P=0.019) but similar perivascular fibrosis. Arteriolar wall area/circumference ratio, a measure of arteriolar wall thickness, was 47% greater in women than men (P=0.012). Cardiomyocyte width and diffusion radius were positively correlated, and capillary length density was negatively correlated with BSA (P<0.05). Whereas cardiomyocyte width, capillary length density, diffusion radius, and cardiomyocyte width/BSA ratio were similar for men and women, women had a greater diffusion radius/BSA ratio (P=0.0038) and a greater diffusion radius/cardiomyocyte width ratio (P=0.027). Women also had lower vascular endothelial growth factor (VEGF) receptor-1 levels (P=0.048) and VEGF receptor-1/VEGF-A ratio (P=0.024) in plasma. We conclude that women with extensive coronary artery disease have greater arteriolar wall thickness and diffusion radius relative to BSA and to cardiomyocyte width than men, which may predispose to myocardial ischemia. Additional studies of larger numbers of women with less extensive coronary artery disease are required to confirm these findings.

Diastolic Dysfunction of Aging Is Independent of Myocardial Structure but Associated with Plasma Advanced Glycation End-Product Levels

Background Heart failure is associated with abnormalities of myocardial structure, and plasma levels of the advanced glycation end-product (AGE) Nε-(carboxymethyl)lysine (CML) correlate with the severity and prognosis of heart failure. Aging is associated with diastolic dysfunction and increased risk of heart failure, and we investigated the hypothesis that diastolic dysfunction of aging humans is associated with altered myocardial structure and plasma AGE levels. Methods We performed histological analysis of non-ischemic left ventricular myocardial biopsies and measured plasma levels of the AGEs CML and low molecular weight fluorophores (LMWFs) in 26 men undergoing coronary artery bypass graft surgery who had transthoracic echocardiography before surgery. None had previous cardiac surgery, myocardial infarction, atrial fibrillation, or heart failure. Results The patients were aged 43–78 years and increasing age was associated with echocardiographic indices of diastolic dysfunction, with higher mitral Doppler flow velocity A wave (r = 0.50, P = 0.02), lower mitral E/A wave ratio (r = 0.64, P = 0.001), longer mitral valve deceleration time (r = 0.42, P = 0.03) and lower early diastolic peak velocity of the mitral septal annulus, e’ (r = 0.55, P = 0.008). However, neither mitral E/A ratio nor mitral septal e’ was correlated with myocardial total, interstitial or perivascular fibrosis (picrosirius red), immunostaining for collagens I and III, CML, and receptor for AGEs (RAGE), cardiomyocyte width, capillary length density, diffusion radius or arteriolar dimensions. Plasma AGE levels were not associated with age. However, plasma CML levels were associated with E/A ratio (r = 0.44, P = 0.04) and e’ (r = 0.51, P = 0.02) and LMWF levels were associated with E/A ratio (r = 0.49, P = 0.02). Moreover, the mitral E/A ratio remained correlated with plasma LMWF levels in all patients (P = 0.04) and the mitral septal e’ remained correlated with plasma CML levels in non-diabetic patients (P = 0.007) when age was a covariate. Conclusions Diastolic dysfunction of aging was independent of myocardial structure but was associated with plasma AGE levels.

Increased tissue kallikrein levels in type 2 diabetes.

Aims/hypothesisWe measured components of the kallikrein–kinin system in human type 2 diabetes mellitus and the effects of statin therapy on the circulating kallikrein–kinin system.MethodsCirculating levels of bradykinin and kallidin peptides, and high and low molecular weight kininogens, as well as plasma and tissue kallikrein, and kallistatin were measured in non-diabetic and diabetic patients before coronary artery bypass graft surgery. Tissue kallikrein levels in atrial tissue were examined by immunohistochemistry and atrial tissue kallikrein mRNA quantified.ResultsPlasma levels of tissue kallikrein were approximately 62% higher in diabetic than in non-diabetic patients (p = 0.001), whereas no differences were seen in circulating levels of bradykinin and kallidin peptides, and high and low molecular weight kininogens, or in plasma kallikrein or kallistatin. Immunohistochemistry revealed a twofold increase in tissue kallikrein levels in atrial myocytes (p = 0.015), while tissue kallikrein mRNA levels were increased eightfold in atrial tissue of diabetic patients (p = 0.014). Statin therapy did not change any variables of the circulating kallikrein–kinin system. Neither aspirin, calcium antagonists, beta blockers or long-acting nitrate therapies influenced any kallikrein–kinin system variable.Conclusions/interpretationTissue kallikrein levels are increased in type 2 diabetes, whereas statin therapy does not modify the circulating kallikrein–kinin system. Cardiac tissue kallikrein may play a greater cardioprotective role in type 2 diabetic than in non-diabetic patients and contribute to the benefits of ACE inhibitor therapy in type 2 diabetic patients. However, our findings do not support a role for the kallikrein–kinin system in mediating the effects of statin therapy on endothelial function.

Obesity Is Associated with Lower Coronary Microvascular Density

Background Obesity is associated with diastolic dysfunction, lower maximal myocardial blood flow, impaired myocardial metabolism and increased risk of heart failure. We examined the association between obesity, left ventricular filling pressure and myocardial structure. Methods We performed histological analysis of non-ischemic myocardium from 57 patients (46 men and 11 women) undergoing coronary artery bypass graft surgery who did not have previous cardiac surgery, myocardial infarction, heart failure, atrial fibrillation or loop diuretic therapy. Results Non-obese (body mass index, BMI, ≤30 kg/m2, n=33) and obese patients (BMI >30 kg/m2, n=24) did not differ with respect to myocardial total, interstitial or perivascular fibrosis, arteriolar dimensions, or cardiomyocyte width. Obese patients had lower capillary length density (1145±239, mean±SD, vs. 1371±333 mm/mm3, P=0.007) and higher diffusion radius (16.9±1.5 vs. 15.6±2.0 μm, P=0.012), in comparison with non-obese patients. However, the diffusion radius/cardiomyocyte width ratio of obese patients (0.73±0.11 μm/μm) was not significantly different from that of non-obese patients (0.71±0.11 μm/μm), suggesting that differences in cardiomyocyte width explained in part the differences in capillary length density and diffusion radius between non-obese and obese patients. Increased BMI was associated with increased pulmonary capillary wedge pressure (PCWP, P<0.0001), and lower capillary length density was associated with both increased BMI (P=0.043) and increased PCWP (P=0.016). Conclusions Obesity and its accompanying increase in left ventricular filling pressure were associated with lower coronary microvascular density, which may contribute to the lower maximal myocardial blood flow, impaired myocardial metabolism, diastolic dysfunction and higher risk of heart failure in obese individuals.

Is there still a role for the classical Cox-Maze III?

Background:  The incidence of surgery for atrial fibrillation (AF) is rising, paralleled by an increase in the types of lesion sets and energy sources used. These alternate energy sources have simplified the surgery at the expense of increased cost of consumables. The classical Cox‐Maze III is the gold standard therapy with a proven efficacy in curing AF. Our complete experience with this procedure is presented.

Surgical Treatment of Ruptured Metastatic Pleomorphic Leiomyosarcoma

A rare case of primary cardiac leiomyosarcoma was diagnosed in a 21-year-old man who presented with a groin mass thought to be a sebaceous cyst. Histopathology revealed a high-grade pleomorphic leiomyosarcoma. Combined positron-emission and computed tomography showed a large metabolically active left atrial mass with multiple metastases. Major debulking resection was undertaken, followed by radiation and chemotherapy. At 13 months postoperatively, limited spread has been detected, and the patient had no limitation in daily life.

Resection of Right Atrial Metastatic Large-Cell Neuroendocrine Carcinoma

The incidence of cardiac metastases is rising due to increasingly sensitive diagnostic investigations and longer patient survival as a result of improved treatment for malignancies. We report a rare case of right atrial metastasis from a large cell neuroendocrine carcinoma successfully resected with cardiopulmonary bypass. The surgical management of advanced cardiac malignancy is discussed. In appropriately selected cases surgical resection of cardiac metastases can be beneficial, allowing improvement in quality of life, and prolongation of life.