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Biomedical subjects

G W Vetrovec

Publications and source records attributed to G W Vetrovec.

At least 19 recordsLinked to original sources
PubMed2005

Impaired coronary and myocardial flow in severe aortic stenosis is associated with increased apoptosis: a transthoracic Doppler and myocardial contrast echocardiography study.

OBJECTIVE: To test the hypothesis that impaired coronary and myocardial blood flow are linked with increased myocyte apoptosis, thus establishing a link between pressure overload and left ventricular (LV) remodelling. METHODS AND RESULTS: Peak diastolic coronary blood flow velocity (CBFV) was evaluated at transthoracic Doppler echocardiography, and signal intensity (SI) and the rate of SI rise (beta) were measured at myocardial contrast echocardiography in 11 patients with severe aortic stenosis and LV hypertrophy. In the same patients, biopsies were obtained from the anterolateral LV free wall during surgery and analysed for cardiomyocyte apoptosis. LV mass corrected CBFV (CBFVI) was significantly lower in patients than in controls (median 0.100 cm.g/s (interquartile range 0.07-0.115) v 0.130 cm.g/s (0.130-0.160), p = 0.002). Similarly, SI*beta was significantly lower in patients than in controls (11 1/s (8-66) v 83 1/s (73-95), p = 0.001). Apoptotic rate was increased in aortic stenosis more than 100-fold versus controls (1.2% (0.8-1.4) v 0.01% (0.01-0.01), p < 0.001) and inversely correlated with lower CBFVI and SI*beta (r = -0.77, p = 0.001 for both). CONCLUSIONS: Patients with severe aortic stenosis and LV hypertrophy have impaired myocardial perfusion, which is associated with enhanced cardiomyocyte apoptosis. Impaired myocardial perfusion and the ensuing oxygen demand-supply imbalance may, at least partially, be responsible for increased apoptosis and possible transition to heart failure, thus establishing a link between pressure overload, LV remodelling, and heart failure.

Aged↗
PubMed1999

Dual anterior interventricular arteries.

A patient with dual left anterior descending (R. interventricularis anterior of the left coronary artery) coronary artery is presented. A normally arising left anterior descending was hypoplastic, and an anomalous left anterior descending, which arose from the right sinus aorticus had a normal caliber. The anomalous left anterior descending artery traversed between the aorta and the pulmonary artery supplying most of the anterior myocardial wall of the left ventricle. This rare coronary anomaly can potentially have implications on percutaneous coronary interventions or on surgical revascularization procedures.

Angioplasty, Balloon, Coronary↗
PubMed1999

Percutaneous revascularization modalities in heart transplant recipients.

Accelerated allograft vasculopathy significantly limits the survival of heart transplant recipients. The prevalence of allograft coronary artery disease is as high as 18% by 1 year and 50% by 5 years following heart transplant. Heart failure and sudden cardiac death are the two most common clinical presentations. In heart transplant recipients with severe, discrete focal allograft vascular disease, percutaneous balloon angioplasty is a viable palliative option. However, its application is limited by a significant restenosis rate and progression of allograft disease in nontreated segments. Diffuse disease with tapering of vessels may be approached by debulking devices. Emerging revascularization modalities for focal stenoses and some of the diffuse tapering vessels include coronary stents, rotational atherectomy, various wavelength lasers, and, to a lesser extent, directional atherectomy. Conceivably, stents will reduce restenosis rates related to focal, discrete plaques; yet it is unknown whether they will be efficacious in short- and long-term treatment of diffusely diseased segments affected by allograft disease. Accurate assessment of clinical outcomes and long-term evaluation is imperative prior to acceptance of these devices as fundamental interventional tools for treatment of allograft coronary artery disease.

Adult↗
PubMed1998

Safety of long-acting dihydropyridine calcium channel blockers in hypertensive patients.

Issues raised recently concerning the safety of calcium channel blockers (CCBs) prompted an analysis of the occurrence of cardiovascular events and death in the Pfizer Inc. hypertension clinical trial databases for amlodipine (Norvasc) and nifedipine in the gastrointestinal therapeutic system (GITS) formulation (Procardia XL). Prospectively defined analyses of data from comparative and noncomparative trials of amlodipine and nifedipine GITS were conducted. Outcome measures included cardiovascular and noncardiovascular deaths, and adverse cardiovascular events including new/worsened angina, myocardial infarction (MI), serious arrhythmia, stroke, congestive heart failure, and bleeding. Among all amlodipine-treated patients (n = 32,920), the incidence rates for all-cause death, MI, and new/worsened angina were 3.0, 3.3, and 1.6/1,000 patient-years of exposure, respectively. Among those in comparative trials alone (n = 4,126), the all-cause death rate was 4.1/1,000 patient-years, which was comparable to that of other non-CCB agents and significantly less than that of other CCBs (23.8/1,000 patient-years, p = 0.015), although the difference in rates represents only 2 deaths. Among all nifedipine-GITS-treated patients (n = 2,645), the rate of all-cause death was 4.1/1,000 patient-years, of MI 6.5/1,000 patient-years, and of new/ worsened angina 5.7/1,000 patient-years. The incidence rates for MI and other cardiac events were low in these hypertension trials, and did not differ among treatment groups in either the amlodipine or nifedipine GITS comparative analyses. In the clinical trial databases analyzed, there is no signal suggesting excessive risk of death or cardiovascular events for hypertensive patients treated with amlodipine or nifedipine GITS.

Amlodipine↗
PubMed1998

Fluoroscopy and selective angiography of left ventricular assist system inflow cannula as a method of detecting cannula entrapment.

Left ventricular assist systems have become an important tool as a bridge to cardiac transplantation. Malfunction of these devices often leads to clinical and hemodynamic deterioration. One potential complication is the obstruction of the inflow cannula secondary to remodeling of the left ventricular cavity. We report two cases where fluoroscopy and selective angiography were used to visualize the orientation and obstruction of the inflow cannula when echocardiographic findings were indeterminant.

Adult↗
PubMed1998

Prior infection with cytomegalovirus is not a major risk factor for angiographically demonstrated coronary artery atherosclerosis.

To determine if cytomegalovirus (CMV) infection is a risk factor for primary coronary artery disease (CAD), the association between CMV infection and CAD (>50% blockage in any coronary artery) was investigated in nearly 900 successive nontransplant patients undergoing coronary angiography. By use of logistic regression, older age (P <.001), white race (P <.001), gender (P <.001), hypercholesterolemia (P = .04), and other established cardiovascular risk factors (P = .003) were identified as significantly associated with CAD, but CMV seropositivity (P = .462), the level of IgG antibodies to CMV whole cell antigen (P = .98), or the levels of IgG antibodies to CMV glycoprotein B (P = .67) were not. These data suggest that CMV infection is not a major risk factor for the development of primary CAD in adults.

Adult↗
PubMed1997

Anatomic variant of the posterior interventricular coronary artery: implications for coronary angioplasty in acute myocardial infarction.

Acute thrombotic occlusion of an infarct-related artery is frequently found in patients presenting with myocardial infarction. In a patient with acute inferior wall myocardial infarction complicated by continuous chest pain and hemodynamic instability, emergency diagnostic coronary arteriography demonstrated a patent, infarct-related, "pseudo" right coronary artery while, in fact, this vessel was a rare anatomic variant of the posterior interventricular branch with very early origin from the right coronary artery and the true right coronary artery was completely occluded by a thrombotic obstruction. Accurate anatomic-angiographic interpretation of the angiogram was crucial for successful performance of emergency recanalization and revascularization of the true right coronary artery with laser and balloon angioplasty. Once antegrade flow was restored another rare coronary variant was discovered, i.e., a sinoatrial node artery arising from the middle portion of the newly patent right coronary artery.

Adult↗
PubMed1996

The stenotic stent: mechanisms and revascularization options.

As demonstrated by the two recent randomized studies of elective, single stent placement versus balloon angioplasty of de novo lesions in the coronary arteries, angiographic restenosis occurs significantly less after stent implantation. However, reported stent restenosis rate varies from 14% to more than 60%, depending on patient characteristics, stent design, number of stents implanted, vessel treated, location of the lesion, and acute luminal gain. The lowest rate of stenosis occurs in de novo lesions. The highest rate of stent restenosis is encountered in multiple stents and in ostial saphenous vein graft lesions. Stent restenosis can be treated with balloon angioplasty with very high success rates. This treatment is associated with remarkably low incidence of complications. Focal stenoses within the stent are more easily treated than are diffuse occlusions. Atherectomy of intrastent stenosis is not recommended. Excimer and holmium: YAG lasers can be applied for revascularization of intrastent lesions considered "not ideal" for balloon angioplasty. Unless thrombus is present or significant dissection detected or angioplasty performed within 2 months following stenting, patients do not require anticoagulants following balloon angioplasty of stent restenosis.

Angioplasty, Balloon, Coronary↗