Assessment of aortic stiffness by transesophageal echocardiography.

BACKGROUND: Aortic stiffness, often measured by the carotid/femoral pulse-wave velocity (PWV) method, has become an attractive predictor for cardiovascular (CV) risk. Although noninvasive, PWV requires additional equipment and training. Aortic diameters measured at transesophageal echocardiography (TEE) provide high spatial resolution images as an alternative to PWV, and permit a more routine assessment of aortic stiffness. The purpose of this study was to measure aortic diameters at TEE, calculate aortic stiffness and compare these data to those of the more established PWV as estimates of CV risk and survival. METHODS: Systolic and diastolic aortic dimensions were measured retrospectively in 500 consecutive patients who had a clinically indicated TEE. Aortic compliance, distensibility, and stiffness index were calculated using the aortic diameters and corrected brachial cuff blood pressures (BP). RESULTS: Compliance significantly related to age and mean BP (both P < 0.0001) and nearly significantly to chronic renal disease (P = 0.064). The results for distensibility and stiffness index were similar. When analyzed by Kaplan-Meier curves, all stiffness tertiles were significantly predictive of 4.5- to 7.5-year survival. These calculated values behaved similar to those of PWV reported in the literature. CONCLUSIONS: This study showed that in patients undergoing routine TEE, aortic stiffness can be readily measured and that the derived values offer relationships comparable to those of PWV, including survival prediction. The method may also find use in assessing aortic stiffness in the TEE evaluation of patients with a bicuspid aortic valve or in preparation for transcatheter aortic valve replacement.

Malignant neurally-mediated syncope: pathophysiology and treatment.

Neurally-mediated syncope is the most common cause of transient loss of consciousness. In this report, we describe an index case of a 43-year-old man with multiple episodes of neurally-mediated syncope. He underwent tilt-table testing, resulting in asystole for 15 seconds with generalized convulsions. After permanent pacemaker implantation, the patient had another syncopal episode requiring adjustment of pacemaker settings. Current concepts of the pathophysiology as well as the diagnosis and management of this condition are discussed.

Hypertension and atrial fibrillation.

Atrial fibrillation (AF) is an emerging public health problem. The most important risk factor for developing chronic AF is uncontrolled hypertension. Uncontrolled hypertension promotes the initiation and perpetuation of AF through atrial remodeling. Experimental evidence has demonstrated the important role of the renin-angiotensin system in atrial remodeling. Retrospective analysis of several large clinical trials and small prospective trials suggests the beneficial role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in preventing the onset and recurrence of AF in different populations. Several large prospective trials with longer follow-up periods are in progress. These trials may provide definitive evidence for the use of these agents in the prevention of AF.

Myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart.

Myocardial stunning refers to contractile dysfunction that persists after an ischemic episode and restoration of coronary blood flow. In this article, 2 cases of myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart are presented. The incidence of this condition is unknown. It is observed that this condition seems to occur in females and in the obese and is generally associated with rapid recovery. This occurrence seems to be brought about by autonomic changes that occur during electroconvulsive therapy. Several drugs have been used to ameliorate the condition, although studies were limited to establish efficacy of regimens.

The spectrum of thrombotic thrombocytopenic purpura: a clinicopathologic demonstration of tacrolimus-induced thrombotic thrombocytopenic purpura in a lung transplant patient.

Immunosuppressive drugs used post-transplantation are among the most common causes of thrombotic thrombocytopenic purpura (TTP). Diagnosis is often confounded not only by its myriad presentations, but also because these manifestations may be explained by the comorbidities or complications of transplantation. A 61-year-old female who had a single lung transplant for severe chronic obstructive pulmonary disease maintained on corticosteroids, tacrolimus and mycophenolate mofetil, was admitted for fever, headache with confusion and lethargy. She was mildly anemic and thrombocytopenic. Peripheral smear showed rare fragmented red cells. Muddy brown casts were present on urinalysis. She was diagnosed with TTP. Tacrolimus was discontinued and the mental status of the patient, anemia and thrombocytopenia improved significantly.

Obesity hypertension: pathophysiological role of leptin in neuroendocrine dysregulation.

Leptin is a 16-kDa peptide hormone that is primarily synthesized and secreted by adipose tissue. One of the major actions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake, elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect mechanisms, may play an important role in cardiovascular and renal regulation. Although the relevance of endogenous leptin needs further clarification, it appears to function as a pressure- and volume-regulating factor under conditions of health. However, in abnormal situations characterized by chronic hyperleptinemia such as obesity, it may function pathophysiologically for the development of hypertension and possibly also for direct renal, vascular and cardiac damage.

Correlation of arterial blood pressure and compliance with left ventricular structure and function in the very elderly.

There are very few data on the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), arterial compliance, and left ventricular structure and function, particularly left ventricular hypertrophy (LVH), in the very elderly (>75 years). SBP and arterial stiffness increase with age, and the question is: which of the two is the main stimulus to LVH? This is a cross-sectional study to compare blood pressure and arterial stiffness measures with regard to their correlations with echocardiographic parameters of LV structure and function, controlling for age and cardiovascular risk factors, in a very elderly population. Arterial stiffness was determined by radial pulse waveform using pulse contour analysis. LV dimensions were measured by transthoracic M-mode echocardiography, and diastolic function by tissue Doppler measurements of diastolic mitral annular velocities. There were 179 subjects, all male, with a mean age of 81.8 years. Using age-adjusted partial correlations, SBP, DBP, and mean arterial pressure (MAP) were correlated with parameters of LV structure and function. Correlation coefficients were: SBP versus left ventricular mass index (LVMI), r = 0.246; SBP versus early diastolic mitral annular velocity (MAV), r = -0.179; DBP versus LVMI, r = 0.199; DBP versus MAV, r = -0.199; MAP versus LVMI, r = 0.276; and MAP versus MAV, r = -0.206, all with P < .05. However, neither capacitative nor reflective arterial compliance was significantly correlated with any parameter of LV structure and function. After controlling for age and 10 cardiovascular and metabolic risk factors, the correlation between blood pressure and the measured LV parameters was substantially unchanged, as was the lack of correlation between indices of arterial compliance and the LV indices. Arterial blood pressure is correlated with LV structure and function in the very elderly, but arterial stiffness, as measured by diastolic pulse contour analysis, is not.