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Biomedical subjects

Stuart J Hutchison

Publications and source records attributed to Stuart J Hutchison.

8 recordsLinked to original sources
PubMed2005

Dehydroepiandrosterone sulfate induces acute vasodilation of porcine coronary arteries in vitro and in vivo.

Although an inverse relationship between dehydroepiandrosterone sulfate (DHEAS) and coronary artery disease has been demonstrated in men, the vascular effects of DHEAS are not well defined. The vasoactive effects of intracoronary DHEAS and testosterone (0.1 nM to 1 microM) were examined in vivo in 24 pigs. Epicardial cross-sectional area was measured by intravascular ultrasound, and coronary flow velocity by intravascular Doppler velocimetry. We also examined the effects of antagonism of the androgen receptor, nitric oxide synthase, and potassium channels on DHEAS-induced vasodilation in vitro in coronary rings from male and female pig hearts. DHEAS and testosterone induced increases in cross-sectional area, average peak velocity, and coronary blood flow. The maximal increase in coronary blood flow in response to testosterone was 1.26-fold (P=0.02), and in average peak velocity 1.43-fold (P=0.05), greater than that to DHEAS, whereas increases in cross-sectional area were similar. Vasodilation to both hormones was rapid, with maximal responses occurring <10 minutes after administration. In vitro, DHEAS and testosterone induced vasodilation in coronary rings, greater with testosterone. At doses of 0.1 and 1 microM, the vasodilator effects of DHEAS and testosterone were inhibited by the androgen receptor antagonist flutamide but not the estrogen receptor antagonist ICI 182,780. At 10 microM, neither DHEAS- nor testosterone-induced vasorelaxation was inhibited by flutamide, ICI 182,780, L-NAME, or deendothelialization, but both were attenuated by pretreatment with glibenclamide. No gender differences were observed in any of the responses examined. In conclusion, DHEAS is an acute coronary artery vasodilator, but less potent than testosterone. Its effect might be mediated via androgen receptors and may involve ATP-sensitive potassium channels.

ATP-Binding Cassette Transporters↗
PubMed2005

Prosthetic valve thrombosis after initiation of hormone replacement therapy.

The complications of hormone replacement therapy (HRT) related to hypercoagulability are well known. However, there have been no cases of prosthetic valve thrombosis reported in the literature in conjunction with HRT. The present report discusses a case of acute mitral prosthetic valve thrombosis associated with the initiation of HRT. Because hypercoagulability is usually associated with significant morbidity and mortality, caution should be exercised in the management of patients with prosthetic valve thrombosis receiving HRT.

Aged↗
PubMed2004

Transthoracic echocardiography to identify or exclude cardiac cause of shock.

BACKGROUND: Transesophageal echocardiography (TEE) is often still considered the echocardiographic test of choice in the general ICU patient population to establish the presence or absence of cardiac cause of shock, and is often requested and performed as the initial and only echocardiographic test. This premise is based on older studies in which transthoracic echocardiography (TTE) commonly offered inadequate images in ICU patients. STUDY OBJECTIVES: We hypothesized that current TTE imaging alone is adequate to identify or exclude cardiac cause of shock in the great majority of cases. METHODS: One hundred consecutive shock cases in which an echocardiogram was requested were prospectively analyzed by two blinded echocardiographers for image adequacy, and the absence or presence of cardiac cause of shock (defined as one or more of the following: severe left ventricular (LV) or right ventricular systolic dysfunction, tamponade, severe left-sided valve disease, or a postinfarction mechanical complication), and compared to a clinical standard of presence/absence of cardiac cause of shock as determined by autopsy, surgery, or objective testing. Shock was defined as systolic BP < 100 mm Hg or fall in BP >/= 25%, and inotrope use or evidence of low output or venous congestion. Cardiac output was determined by the LV outflow tract (LVOT) Doppler method. RESULTS: Sixty-three percent of cases had a cardiac cause of shock. TTE image quality was adequate in 99% cases. Among the 99% of cases in which the imaging was adequate, the sensitivity of TTE for cardiac cause of shock was 100%, the specificity was 95%, the positive predictive value was 97%, and the negative predictive value was 100%. There were relative contraindications to TEE in 15% of cases. Stroke volume index (15 +/- 6 mL/m(2) vs 31 +/- 7 mL/m(2) [mean +/- 1 SD]; p < 0.001) and cardiac index (1.6 +/- 0.5 mL/min/m(2) vs 2.9 +/- 0.9 mL/min/m(2); p < 0.001) were significantly less in the group with a cardiac cause of shock than in the group with a noncardiac cause of shock. CONCLUSIONS: In the general critical care population, current TTE imaging identifies the great majority of cardiac causes of shock. TTE should be considered not only the initial, but also the principal echocardiographic test in the critical care environment.

Aged↗
PubMed2003

Contrast echocardiography remains positive after treatment of pulmonary arteriovenous malformations.

STUDY OBJECTIVES: Pulmonary arteriovenous malformations (PAVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) can cause hemorrhage, stroke, and cerebral abscess. Therapy consists of transcatheter embolotherapy (TCET) to occlude the PAVMs. Contrast transthoracic echocardiography (TTE) can be used to screen for PAVMs, but little is known about the performance of contrast TTE after TCET has been performed. Our objective was to determine the effect of the successful performance of TCET on the performance of contrast TTE, specifically, in what proportion of patients the findings of contrast TTE normalized or remained positive after the performance of TCET. DESIGN: Retrospective chart review. SETTING: HHT clinic at university teaching hospital. PATIENTS: Patients who have undergone TCET for the treatment of PAVMs. INTERVENTIONS: Patients were screened for PAVMs with a chest radiograph (CXR), oxygen shunt test (OST), and contrast TTE. Pulmonary angiography was recommended for patients with any positive findings on a screening test. PAVMs > or = 3 mm were occluded by TCET. Contrast TTE, OST, and CXR were performed approximately 1 month later. The results of contrast TTE before and after patients underwent TCET were compared. MEASUREMENTS AND RESULTS: Thirty-nine patients underwent contrast TTE prior to undergoing TCET, and 29 patients underwent contrast TTE both prior to and after undergoing TCET. In all patients, TTE findings were positive prior to TCET. All PAVMs with feeding vessels > or = 3 mm were successfully occluded based on completion angiography. After TCET, 48% of patients had no detectable residual PAVMs, and the remainder had small (ie, < 3 mm) residual PAVMs. Of the 29 patients, 90% had positive contrast TTE findings after undergoing TCET. In the subset of patients who had no residual PAVMs on the completion angiography, 80% had positive contrast TTE findings after undergoing TCET. CONCLUSIONS: In most patients, contrast TTE findings remain positive after they undergo TCET, even in patients without residual PAVMs seen on angiography. This may reflect residual PAVMs that are too small to visualize using angiography. These findings have important implications for the follow-up and management of HHT patients.

Adult↗
PubMed2002

The 'wet Westermark' sign.

A 67-year-old woman experienced dyspnea and exertional intolerance after aortocoronary bypass grafting. Early in the postoperative course, she had mild heart failure due to volume overload. Regional oligemia was appreciated on the chest radiograph. The oligemia led to the consideration of pulmonary embolism and was corroborated by perfusion scanning, which demonstrated defects in the same areas. Interstitial markings, accentuated by the heart failure, served as a serendipitous form of radiographic 'contrast' - a marker of blood perfusion and, in the present case, regional underperfusion. Therefore, mild heart failure accentuates 'Westermark's' sign.

Aged↗
PubMed2002

Right heart obstruction from a balloon-like sinus of Valsalva aneurysm in a patient with Down syndrome.

A 40-year-old man with Down syndrome presented with right heart failure. He was markedly obese and had severe developmental delay. There was marked edema and an early diastolic sound. Transthoracic echocardiography suggested a right heart mass. Transesophageal echocardiography revealed an unruptured balloon-like sinus of Valsalva aneurysm within the right atrium that obstructed the tricuspid orifice. The patient died in hospital of mixed obstructive and/or septic shock.

Adult↗
PubMedDate not supplied

Cardiac encasement by metastatic myxoid liposarcoma.

Isolated cardiac metastasis from a primary liposarcoma of noncardiac origin is a rare occurrence. A patient who presented with biventricular failure and constrictive hemodynamics years after successful resection of a primary liposarcoma of the thigh is described. Extensive cardiac encasement by tumor was suspected on diagnostic imaging. Hemodynamic instability and multiorgan failure necessitated urgent exploratory sternotomy. The patient died intraoperatively. Extensive metastatic sarcoma limited to the heart was confirmed during surgical procedure. This case suggests that in clinical and pathological investigation of a cardiac mass, knowledge of previous extracardiac involvement with soft tissue sarcoma is essential.

Fatal Outcome↗