PubMed Health⌕ Search

Biomedical subjects

S Duvvuri

Publications and source records attributed to S Duvvuri.

12 recordsLinked to original sources
PubMed2000

In vivo demonstration of an antithrombin effect of abciximab.

Abciximab prolonged the activated clotting time (ACT) in a post hoc analysis from the Evaluation of IIb/IIIa Platelet Receptor Antagonist 7E3 in Preventing Ischemic Complications trial and an in vitro study has suggested an antithrombin effect of platelet glycoprotein IIb/IIIa inhibition. The purpose of this study was to evaluate the in vivo effects of abciximab on ACT and thrombin generation. In 46 patients undergoing coronary intervention, 24 received heparin and abciximab (group I), whereas 22 received heparin alone (group II). All received the same dose (70 U/kg) of heparin. Heparin was given after a baseline ACT, and in group I, abciximab was administered after the 5-minute ACT. Serial ACTs were recorded at baseline, 5, 10, 20, and every 30 minutes thereafter and at the procedure's end. No intervention including balloon angioplasty was performed until after the 20-minute ACT. The prothrombin fragment F1.2 (Nm/L) was measured at baseline, 20 minutes, and at the end of the procedure. Before (baseline) heparin and at 5 minutes, ACTs were similar. Abciximab prolonged ACT by a mean of 34 to 64 seconds starting with the 10-minute ACT and extending to the 50-minute ACT (all p <0.01 vs heparin alone). There was a progressive decrease in the F1.2 with abciximab, and baseline minus end F1.2 was 0.12 +/- 0.02 in group I versus 0.05 +/- 0.04 in group II, p <0.05. These data indicate a significant in vivo effect of abciximab plus heparin in increasing ACT and decreasing F1.2, results that are consistent with an effect on reducing thrombin generation.

Abciximab↗
PubMed1999

Rotational atherectomy: improved procedural outcome with evolution of technique and equipment. Single-center results of first 1,000 patients.

We present our single-center experience of rotational atherectomy (RA) in the first 1,000 consecutive patients divided arbitrarily into three different time periods corresponding to significant changes in technique or equipment for RA. Period I (August 1994 to April 1995; 172 cases) is characterized by early experience, longer ablation, and frequent use of intra-aortic balloon pump; period II (May 1995 to January 1996; 254 cases) is characterized by short ablation runs (20-30 sec) and use of rotaflush; period III (February 1996 to February 1997; 574 cases) is characterized by ReoPro use, neosynephrine boluses to avoid hypotension, and rota floppy wire and flexible shaft burrs. The procedural success rate has improved and complication rates have progressively declined over these three time periods. The incidence of lesion complexity (long and type C lesions) and patients with unstable rest angina have increased over these time periods of RA. Therefore, modification in procedural techniques and equipment over time have made RA a safe technique despite its use in very complex lesion subsets.

Aged↗
PubMed1999

The effect of early postinfarction revascularization of asymptomatic patients on left ventricular remodeling.

BACKGROUND: Patients with angina after a Q-wave myocardial infarction benefit from elective revascularization, but it is not known whether asymptomatic patients, including those with a totally occluded infarct-related artery, improve after revascularization. OBJECTIVE: To determine the effect of early postinfarction revascularization of asymptomatic patients on left ventricular remodeling. METHODS: We prospectively studied 31 consecutive asymptomatic patients (aged 57 +/- 2 years, 24 with anterior infarcts) after Q-wave myocardial infarction with > or = 70% stenosis of the infarct-related artery (IRA) who underwent early elective revascularization (days 4-10 after myocardial infarction). Group I consisted in patients with a totally occluded IRA (n = 10), and group II consisted in patients with a patent, though stenosed, IRA (n = 21). Resting echocardiography and low-dose dobutamine echocardiography were performed at baseline (day 3 +/- 1), and rest echocardiography was repeated after an 8-week follow-up. Significant myocardial viability was defined as > or = 2 wall segments improved (in a 16-segment model of left ventricle) versus baseline, and significant functional recovery as > or = 2 segments improved versus baseline on follow-up examination. Left ventricular end-systolic volume indices (ESVI) and end-diastolic volume indices and ejection fractions were measured by using a modified version of Simpson's rule (using apical two-chamber and four-chamber views). RESULTS: The left ventricular ESVI of patients in group I had decreased by 4.2 +/- 1.9 ml/m2, whereas for patients in group II the left ventricular ESVI had increased by 4.2 +/- 1.7 ml/m2 (P = 0.006). Similarly, the left ventricular end-diastolic volume index had decreased by 0.7 +/- 2.4 ml/m2 versus baseline at follow-up for patients in group I and increased by 7.8 +/- 2.1 ml/m2 for patients in group II (P = 0.02). The left ventricular ejection fraction increased by 7.3 +/- 3% for patients in group I and decreased by 0.4 +/- 2% for patients in group II (P = 0.04). CONCLUSION: There is less global left ventricular remodeling, a potentially deleterious process, after elective revascularization early after Q-wave myocardial infarction in asymptomatic patients who had had a totally occluded IRA before revascularization than there is in patients who had already had a patent, though stenosed, IRA before revascularization. These results suggest that restoration of patency of IRA after a Q-wave myocardial infarction is beneficial even for asymptomatic patients.

Coronary Disease↗
PubMed1998

Rotational atherectomy for in-stent restenosis: acute and long-term results of the first 100 cases.

OBJECTIVES: This study evaluated the clinical safety and long-term results of rotational atherectomy (RA) followed by low-pressure balloon dilatation (percutaneous transluminal coronary angioplasty [PTCA]) for the treatment of in-stent restenosis (ISR). BACKGROUND: In-stent restenosis is associated with a high incidence of recurrence after interventional treatment. Because ISR is due to neointimal hyperplasia, rotational ablation may be a more effective treatment than PTCA. METHODS: Between November 1995 and November 1996, 100 consecutive patients with first-time ISR were treated by RA. Quantitative coronary angiography and intravascular ultrasound (IVUS) were used to analyze the acute procedural results. The incidence of repeat in-stent restenosis and target vessel revascularization (TVR) at follow-up was determined. RESULTS: Procedural success without any major in-hospital complications was achieved in 100% of cases. Slow flow was observed in 3% and creatine kinase-MB enzyme elevation >3x normal occurred in 2%. The mean burr-to-artery ratio was 0.68+/-0.18 and adjuvant balloon dilatation was performed at 4.2+/-2.1 atm. Minimum luminal diameter increased from 0.86+/-0.28 mm to 1.89< or =0.21 mm after RA and to 2.56+/-0.29 mm after adjunct PTCA. Quantitative IVUS analysis showed that 77% of the luminal gain occurred due to rotational ablation of the restenotic tissue and only 23% occurred after adjunct balloon dilation, and further stent expansion did not contribute to the luminal enlarge. ment. At a mean follow-up of 13+/-5 months, repeat in-stent restenosis occurred in 28% of patients with TVR of 26%. Univariate predictors of repeat restenosis were burr-to-artery ratio <0.6, ISR in <90 days of stenting, ostial lesion, stent for a restenotic lesion and diffuse type ISR. CONCLUSIONS: Rotational atherectomy is a safe and feasible technique for treatment of ISR and is associated with a relatively low recurrent restenosis in comparison to historical controls of balloon angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1998

Histopathological correlates of early arterial recoil following directional coronary atherectomy.

Elastic recoil has been implicated in the pathophysiology of restenosis after conventional balloon angioplasty alone. Directional atherectomy may attenuate arterial recoil by removing the internal elastic lamina and medial smooth muscle cells and altering the vessel wall architecture. This study sought to evaluate early recoil after directional atherectomy and its relation with excision of deep arterial wall structures. We prospectively evaluated the correlation of the histopathologic evidence of media or adventitia as assessed in the atheroma retrieved during the procedure with the early changes in minimal lumen diameter after directional atherectomy followed by adjunct balloon dilatation in 50 consecutive cases. Recoil was assessed by routinely performed 1- and 15-min postprocedure angiograms, and patients were divided into two groups according to the absence (group I, n = 26) or presence (group II, n = 24) of recoil. The mean changes in minimal luminal diameter between 1 and 15 min was +0.22 mm in group I and -0.14 mm in group II. The absence of recoil was strongly associated with evidence of media tissue in the pathologic analysis as compared with cases with recoil (42 vs. 18%, respectively; p = 0.02). Similarly, retrieval of adventitia was seen exclusively in the group without recoil (15 vs. 0%; p = 0.06). Vessels that underwent recoil had significantly larger reference and immediate postprocedure minimal luminal diameters (3.62 +/- 0.57 and 3.02 +/- 0.45 mm, respectively) as compared with arteries with no recoil (3.28 +/- 0.35 and 2.75 +/- 0. 43 mm, respectively; p < 0.05 for both). Therefore, early luminal changes, likely related to elastic recoil, correlated with excision of deep wall structures during directional atherectomy. Arteries that showed recoil were larger, possibly due to thicker muscular layer and/or larger plaque burden as compared with arteries that did not recoil. Thus, optimal tissue debulking during directional atherectomy appears to attenuate recoil, providing an additional insight into the mechanism of action of this percutaneous revascularization device.

Angioplasty, Balloon, Coronary↗
PubMed1998

Directional coronary atherectomy in acute myocardial infarction.

Balloon angioplasty (percutaneous transluminal coronary angioplasty, PTCA) is an established common strategy in the treatment of acute myocardial infarction (MI) with high success rates but a 5-10% incidence of reclosure/reinfarction due to thrombus and/or intimal flaps. Directional coronary atherectomy (DCA) by removing plaque/thrombus and achieving larger postprocedural luminal diameter may further decrease the incidence of reclosure/reinfarction, with a resultant better in-hospital outcome in this setting. We analyzed the clinical, procedural and in-hospital outcome of patients who underwent DCA or PTCA within 48 h of MI. Long lesions (>20 mm), large angiographic intracoronary thrombus, lesions in a bend, heavy calcification, and vessel diameter <3.0 mm were excluded from the study. Although slow flow occurred more frequently during DCA (17 vs. 9% during PTCA, p = 0.04), procedural success (<50% final diameter stenosis with TIMI-3 flow) was achieved in 96% of DCA and 92% of PTCA group (nonsignificant). Acute closure occurred in 9% of the PTCA group versus 2% of the DCA (p = 0.05), and the composite endpoint of in-hospital reinfarction, reintervention, bypass surgery or death was present in 9% of PTCA cases versus none of DCA cases (p = 0.03). There were no major peripheral vascular complications requiring surgery in either group. Therefore, DCA appears safe and effective in selected patients with recent MI, and is associated with a low incidence of major clinical complications.

Aged↗
PubMed1997

A single-step stent delivery, deployment, and expansion system.

Placement of intracoronary stents now comprises a significant number of the percutaneous coronary revascularization procedures being performed in high-volume interventional laboratories in the United States. Stents have become popular because of the reliable acute results, and decreased restenosis. The most common stent currently in use in the United States is the Palmaz-Schatz balloon-expandable stent (PS stent). This stent delivery system (SDS) usually requires predilatation with a balloon and another dilatation, after stent deployment, with a high-pressure balloon in order to adequately expand the stent. We report on a new hybrid stent-delivery system using the PS stent, the sheath from the SDS, and an NC Bandit balloon. This new hybrid system is safe and significantly decreases the procedure time, fluoroscopy time, and need for additional stents due to angiographic dissection resulting from inexact positioning of the high-pressure balloon within the initially deployed stent, and/due to inadequate placement of the first stent. This may be an ideal delivery system for single stent deployment using currently approved FDA equipment.

Angioplasty, Balloon, Coronary↗
PubMed1996

Use of a pneumatic compression system (FemoStop) as a treatment option for femoral artery pseudoaneurysms after percutaneous cardiac procedures.

Pseudoaneurysm (PA) formation is a well-documented complication of femoral arterial puncture in patients undergoing percutaneous cardiac procedures. Besides surgical repair, there has been success in obliterating the PAs by Duplex ultrasound guided compression (mostly those < 4.0 cm). We analyzed the use of prolonged femoral compression using a pneumatic compression system (FemoStop by USCI) in 10 patients who developed femoral PAs following an interventional cardiac procedure. All PAs were diagnosed by ultrasound and had unsuccessful duplex-guided compression. The size of the PA ranged from 2.8-4.0 cm in diameter. All patients had the FemoStop system placed over the PA with continuous pressure for 12-18 hr. PA obliteration was successful in 90% of cases as confirmed by ultrasound. The only complication observed was skin abrasion in two patients. Our results indicate that the FemoStop system is a simple and effective technique for treatment of femoral artery PAs.

Aged↗
PubMed1993

Comparison of dobutamine and exercise echocardiography for detecting coronary artery disease.

There has been no study comparing the efficacy of dobutamine and exercise echocardiography in detecting coronary artery disease (CAD) or their physiologic effects at ischemic threshold in the same group of patients. To accomplish this, 52 patients presenting for coronary angiography underwent supine ergometer exercise and dobutamine echocardiography. Compared with angiography, the overall sensitivity of detecting CAD was 78% for exercise and 86% for dobutamine echocardiography (p = NS). The sensitivities of detecting patients with 1-, 2-, 3- and multivessel CAD with exercise echocardiography were 63, 80, 100 and 90%, respectively, and with dobutamine echocardiography 75, 90, 100 and 95%, respectively (p = NS, exercise vs dobutamine). The specificity of both tests was 87%. At ischemic threshold, heart rate was significantly lower with dobutamine than with exercise echocardiography (91 +/- 3 vs 114 +/- 3 beats/min; p < 0.001), systolic blood pressure was significantly lower with dobutamine testing (155 +/- 5 vs 176 +/- 6 mm Hg; p < 0.01), and rate-pressure product was significantly lower with dobutamine stress (14.1 +/- 0.7 vs 19.8 +/- 0.8 x 10(3) beats/min x mm Hg; p < 0.001). It is concluded that the efficacy of detecting CAD by exercise and dobutamine echocardiography is comparable, and the physiology at ischemic threshold of the 2 methods is significantly different and suggests a different means of inducing myocardial ischemia.

Aged↗