PubMed Health⌕ Search

Biomedical subjects

Ehtisham Mahmud

Publications and source records attributed to Ehtisham Mahmud.

At least 19 recordsLinked to original sources
PubMed2007

Treatment of recurrent pulmonary vein stenoses with endovascular stenting and adjuvant oral sirolimus.

The increasing use of radiofrequency catheter ablation for the cure of atrial fibrillation has led to iatrogenic pulmonary vein stenosis as a new clinical entity. The optimal diagnostic modality and treatment for pulmonary vein stenosis and restenosis remain unclear. We report the successful treatment of pulmonary vein restenosis following percutaneous balloon angioplasty, and for the first time, following surgical bovine pericardial patch angioplasty, with endovascular stenting and adjuvant oral sirolimus. Both patients remain asymptomatic at 1 year follow-up without evidence of restenosis.

Administration, Oral↗
PubMed2006

Imaging vulnerable plaque by ultrasound.

Diagnostic techniques to identify vulnerable plaques are rapidly evolving. Intravascular ultrasound (IVUS) has the ability to detect and localize plaque as well as quantitate plaque burden. Recent IVUS studies have suggested that patients presenting with acute coronary syndromes have an approximate 25% incidence of additional ruptured plaques in arteries other than the culprit lesion. The ability of IVUS to detect vulnerable plaques before rupture is currently being evaluated by novel techniques. Initially, IVUS was shown to be able to characterize plaque broadly as calcified or fibrofatty but was limited in its ability to more precisely detect lipid-rich plaques, necrotic cores, and thrombus. Recent advances in new applications of IVUS, such as integrated backscatter, wavelet analysis, and virtual histology, have focused on evaluating and mathematically transforming the radiofrequency signal from ultrasound waves into a color-coded representation of plaque characteristics such as lipid, fibrous tissue, calcification, and necrotic core. In addition, targeted contrast agents, applicable to both intravascular and transthoracic studies, are being evaluated in experimental models and aim to highlight specific plaque components, such as endothelial adhesion molecules and other plaque components that might be useful in targeting vulnerable plaques. These advances pave the way for future clinical trials in assessing the ability of such techniques to diagnose vulnerable plaques and to assess the effects of both pharmacologic and mechanical therapies on plaque characteristics.

Atherosclerosis↗
PubMed2006

Monitoring platelet inhibition after clopidogrel with the VerifyNow-P2Y12(R) rapid analyzer: the VERIfy Thrombosis risk ASsessment (VERITAS) study.

INTRODUCTION: Clopidogrel inhibits platelet P2Y12 ADP receptors, while ADP, as an inductor of aggregation, stimulates both P2Y12 and P2Y1 platelet receptors. Despite a clinical loading dose routine with clopidogrel, some patients still experience coronary stent thrombosis suggesting persistent platelet activation. The VerifyNow-P2Y12 is a rapid assay that test platelet activity over 3 min and uses of the combination of ADP and prostaglandin E1 (PGE1) to directly measure the effects of clopidogrel on the P2Y12 receptor. ADP is used to maximally activate the platelets by binding to the P2Y1 and P2Y12 platelet receptors, while PGE1 is used to suppress the ADP-induced P2Y1-mediated increase in intracellular calcium levels. OBJECTIVE: The VERIfy Thrombosis risk ASsessment (VERITAS) was a prospective study designed to measure platelet response to clopidogrel therapy in subjects with multiple risk factors or history of vascular disease using this novel point-of-care assay. METHODS: 166 participants were enrolled in 4 participating sites. Data from 147 participants were analyzed after exclusion of 19 patients due to protocol violations. Platelets were assessed twice at baseline (before clopidogrel) and at 24 h post-loading 450 mg (110 participants) or 7 days after chronic clopidogrel treatment (75 mg/day) (37 patients). All participants received aspirin 81-325 mg for at least 2 days before the study enrollment. Results from the VerifyNow-P2Y12 assay are reported in P2Y12 reaction units (PRU). RESULTS: Clopidogrel therapy resulted in a mean 64.0+/-25.3% PRU reduction. No participant reached PRU inhibition below 10% of baseline. Distribution of PRU values for the VerifyNow-P2Y12 assay shows a separation from baseline to post-clopidogrel assay values with some overlap due to high inter-individual variations in response. CONCLUSIONS: VerifyNow-P2Y12 is a reliable, fast and sensitive device suitable for monitoring of platelet inhibition during clopidogrel therapy.

Adenosine Diphosphate↗
PubMed2006

Fibromuscular dysplasia of renal arteries: percutaneous revascularization based on hemodynamic assessment with a pressure measurement guidewire.

Fibromuscular dysplasia (FMD) leading to renal artery stenosis and hypertension is one of the most common treatable causes of secondary hypertension. However, frequently it can be difficult to judge the anatomical severity of a stenotic lesion with various noninvasive and invasive imaging modalities. We present two patients with poorly controlled hypertension and FMD affecting the renal arteries, in whom there were no anatomically significant stenoses by renal magnetic resonance angiography or selective renal artery angiography. Utilizing a 0.014'' high fidelity micromanometer tipped PressureWire XT (Radi, Reading, MA), to measure intravascular pressure gradients throughout the diseased renal arteries, we identified physiologically significant stenoses, and successfully treated both patients with percutaneous transluminal angioplasty.

Adult↗
PubMed2006

Successful utilization of a novel aspiration thrombectomy catheter (Pronto) for the treatment of patients with stent thrombosis.

Stent thrombosis is a rare but catastrophic complication of percutaneous coronary intervention (PCI). Thrombolytic therapy is ineffective for the treatment of patients with stent thrombosis, while primary PCI in such patients is limited by a high thrombus burden in the culprit vessel often leading to distal embolization and extensive tissue infarction. We present three patients with stent thrombosis successfully treated with the adjunctive use of a novel and new aspiration thrombectomy device (Pronto).

Angioplasty, Balloon, Coronary↗
PubMed2005

Treatment of ischemic stroke complicating cardiac catheterization with systemic thrombolytic therapy.

Ischemic stroke is a rare but serious complication of cardiac catheterization. We report a case in which systemic thrombolytic therapy was successfully utilized in treating a patient with a cerebellar stroke, leading to obtundation during elective cardiac catheterization. Underlying bilateral vertebrobasilar disease with thrombotic embolization to the basilar artery was postulated to be the pathophysiological basis for the stroke and subsequent success of thrombolytic treatment in this patient. As the consequences of this rare complication are severe, systemic thrombolytic therapy should be considered for patients suffering an acute ischemic stroke during cardiac catheterization or percutaneous coronary intervention.

Aged↗
PubMed2005

Catheter-induced vasospasm of both the right external iliac and right coronary arteries during coronary angiography.

Catheter-induced vasospasm is well appreciated during diagnostic coronary angiography and angioplasty, but has rarely been described in peripheral arteries. We present an unusual case of concomitant catheter-induced vasospasm of the right external iliac and right coronary arteries. This case illustrates the potential challenges in diagnosing catheter-induced vasospasm from fixed obstructive atherosclerotic lesions in peripheral vessels.

Adult↗
PubMed2005

Expanded applications of rotational atherectomy in contemporary coronary and peripheral interventional practice.

Percutaneous rotational atherectomy is mainly utilized in contemporary interventional practice to alter lesion compliance, facilitating stent delivery and antirestenotic drug delivery at the site of the underlying lesion. This enables a percutaneous revascularization strategy in a group of patients who would otherwise require a surgical revascularization. We identify and present three novel uses for this device in percutaneous coronary and peripheral interventional procedures, which further expands the applications of rotational atherectomy.

Aged↗
PubMed2004

Does lowering pulmonary arterial pressure eliminate severe functional tricuspid regurgitation? Insights from pulmonary thromboendarterectomy.

OBJECTIVES: Because pulmonary thromboendarterectomy (PTE) can result in an immediate reduction in pulmonary artery (PA) pressure, we sought to evaluate the effect of PTE on severe tricuspid regurgitation (TR) without tricuspid annuloplasty. BACKGROUND: Few data exist regarding the frequency and magnitude of functional TR improvement after reduction in PA pressure. METHODS: We identified 27 patients with severe TR, defined by a regurgitant index (RI) >33%, who underwent PTE. The RI, tricuspid annular diameter (TAD), apical displacement of leaflet coaptation, and estimated PA systolic pressure were determined on pre- and post-PTE echocardiograms. Patients were stratified based on resolution (RI < or =33%) or persistence (RI >33%) of severe TR. RESULTS: Comparing pre- and post-PTE echocardiography results, severe TR resolved in 19 of 27 (70%) patients. This group had a more effective PA systolic pressure reduction after PTE (49 +/- 20 mm Hg vs. 32 +/- 16 mm Hg by echocardiography, p = 0.075, and 37 +/- 16 mm Hg vs. 16 +/- 13 mm Hg by catheter measurement, p = 0.004). No difference was observed in TAD, apical displacement of the tricuspid valve, or other features compared with the group with persistent severe TR. There was a trend toward longer hospital stays in the group with persistent severe TR (19 +/- 15 days vs. 14 +/- 9 days; p = 0.55). CONCLUSIONS: After significant PA pressure reduction by PTE, severe functional TR with a dilated annulus may improve without annuloplasty despite dilated tricuspid annulus diameters.

Adult↗
PubMed2004

Usefulness of compensatory hyperkinesis in the noninfarcted left ventricular wall in separating single from multivessel coronary artery disease in patients with initial ST-elevation acute myocardial infarction.

We assessed the contractility of the contralateral wall on 2-dimensional echocardiography in 50 patients with an initial ST-elevation acute myocardial infarction who underwent coronary angiography. Compensatory hyperkinesis, which we defined as a fractional thickening of >/=60% in the contralateral wall, was a strong predictor of single-vessel coronary artery disease, with a positive predictive value of 85%.

Aged↗
PubMed2004

Severe ostial saphenous vein graft disease leading to acute coronary syndromes following proximal aorto-saphenous anastomoses with the symmetry bypass connector device: is it a suture device or a "stent"?

The Symmetry Bypass Connector (St. Jude Medical, St. Paul, Minnesota) is a nitinol, star-shaped device that was designed to facilitate placement of sutureless aorto-saphenous anastomoses during off-pump coronary artery bypass graft surgery (CABG). Although the device is approved for clinical use in Europe and the U.S., its short- and long-term safety and efficacy are not established. We report on 5 of 121 patients undergoing CABG who presented with an acute coronary syndrome two to five months following placement of this device. In each patient, all saphenous vein grafts (SVGs) placed (n = 11) with the device were totally occluded (n = 6) or compromised by ostial stenoses (n = 5). Treatment consisted of repeat CABG in one patient and percutaneous coronary intervention (PCI) in four patients with cutting balloon atherotomy and stenting. Following PCI, two of four patients presented again within two months with near-occlusive ostial restenosis in all stents placed. Intracoronary ultrasound showed severe neointimal hyperplasia, but only at the proximal interface of the device and stent. One patient was treated with brachytherapy in two SVGs but had a recurrence four months later and was treated with drug-eluting stents in both restenotic segments. Recalcitrant neointimal hyperplasia is postulated to be involved in the pathogenesis of anastomotic device stenosis, possibly similar to in-stent restenosis. Prospective randomized clinical trials are needed to assess the clinical safety and efficacy of this device. Pending such studies, consideration should be given in limiting its use to cases of unacceptably high risk of stroke during aortic cross-clamping. Dual antiplatelet agents, evaluation for ischemia, and close follow-up are warranted in patients that have already received the device.

Acute Disease↗
PubMed2004

Concomitant coronary and multiple arch vessel stenoses in patients treated with external beam radiation: pathophysiological basis and endovascular treatment.

External beam radiation-induced stenoses isolated to the coronary arteries or peripheral vessels have been previously described. We report for the first time the clinical presentation of two patients with concomitant coronary artery and multiple arch vessel disease following external beam radiation of the chest. We review the pathophysiology, discuss the treatment options and describe the percutaneous treatment of coronary, carotid, subclavian, and axillary stenoses related to this rare but likely underdiagnosed disorder.

Aged↗
PubMed2003

Patients at low risk for periprocedural myocardial infarction can be identified by assessment immediately following percutaneous coronary intervention.

Despite utilizing optimal anticoagulant therapy during percutaneous coronary intervention (PCI), the incidence of periprocedural myocardial infarction (PPMI) remains 5 7% and evaluation of preprocedural clinical/angiographic characteristics has failed to reliably predict the likelihood of a PPMI. We hypothesized that immediate post-PCI assessment could identify a group of patients at very low risk for PPMI. A consecutive series of 258 PCI patients was stratified into 3 groups based on immediate post-PCI assessment. Group I (PPMI not expected) included those with an acceptable angiographic result of treated vessel (residual stenosis < 50%), TIMI 3 flow and absence of any intraprocedural complications. Group II (PPMI not unexpected) included those with an acceptable angiographic result, TIMI 3 flow but with any/all of the following: saphenous vein graft (SVG) PCI, transient closure of culprit vessel or major sidebranch, intracoronary thrombus, prolonged chest pain, electrocardiographic (ECG) changes, hypotension, resolved slow flow/no reflow, bailout glycoprotein IIb/IIIa inhibitor use, loss of a minor sidebranch or any angiographic residual stenosis > 50% with TIMI 3 flow. Group III (PPMI expected) included those with any angiographic result of native coronary artery or SVG with < TIMI 3 flow, unresolved chest pain, hypotension or ECG changes at the end of the PCI, loss of a major sidebranch or vessel, or persistent no-reflow. Group stratification was analyzed in relation to the incidence of PPMI (CK-MB > 3 times the upper limit of normal; 18 24 hours post-PCI). Rate of PPMI: Group I (1/141; 0.7%), Group II (7/71; 9.9%), Group III (5/11; 45.5%) (p < 0.001). The 3 groups did not differ in age, clinical presentation or stent use (p = NS). Sixty out of 105 patients (57.1%) with unstable angina, seventy-seven out of 146 patients (52.7%) with B2/C lesions, and 105/180 patients (58.3%) with unstable angina or B2/C lesions were stratified to Group I. This study demonstrates that immediate post-PCI evaluation of the clinical/angiographic characteristics can predict the likelihood of PPMI and a group of patients at a very low risk for a PPMI can be identified, in whom implications exist for limited hospitalization and post-procedural antithrombotic therapy.

Aged↗