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Biomedical subjects

G V Sharma

Publications and source records attributed to G V Sharma.

At least 19 recordsLinked to original sources
PubMed1994

Identification of unstable angina patients who have favorable outcome with medical or surgical therapy (eight-year follow-up of the Veterans Administration Cooperative Study).

To identify patients with unstable angina (UA) who have favorable outcomes with medical therapy or surgery, 468 patients who had been randomized in the Veterans Administration Cooperative Study of UA were risk-stratified based on angiographic criteria of the number of coronary arteries diseased and left ventricular ejection fraction (LVEF). Patients at high risk for UA were defined as those with 3-vessel disease or LVEF of < or = 58%, and patients at low risk were those with 1- or 2-vessel disease and LVEF of > 58%. Of the 468 UA patients randomized, 287 patients belonged to the high-risk and 181 to the low-risk category. In the low-risk group, cumulative mortality after 8 years of follow-up was significantly lower in the medically treated patients (16.8%) than in the surgically treated patients (32.2%) (p = 0.022); in the high-risk group, cumulative mortality was significantly lower in the surgically treated patients (24.1%) than in the medically treated patients (35.3%) (p = 0.03). The relative risk of surgery (the ratio of surgical to medical risk) in the low-risk patients was 1.67, indicating a significant survival advantage with medical treatment (p = 0.05), whereas the relative risk of surgery for the high-risk group was 0.71, indicating a significant survival benefit with surgical treatment (p < 0.05). Thus, medical therapy appears to be the preferred therapy for UA patients with only 1- or 2-vessel disease and normal LVEF, and surgery is preferred for UA patients with 3-vessel disease or LVEF in the lowest tercile.

Angina, Unstable↗
PubMed1994

Pulmonary embolism manifesting as acute disturbances of behavior in patients with spinal cord injury.

Pulmonary embolism (PE) presented with short lived behavioral disturbances (BD) in four out of 13 consecutive patients with a proven PE. Three patients died of PE with evidence of recurrent thromboembolic disease at autopsy and one survived with PE (demonstrable by lung scanning). It is concluded that an acute behavioral disturbance in the acute spinal cord injury (SCI) patient can indicate PE, and the recognition of this possibility should lead to prompt investigation for pulmonary embolism.

Adult↗
PubMed1994

Long-term graft patency (3 years) after coronary artery surgery. Effects of aspirin: results of a VA Cooperative study.

BACKGROUND: The long-term success of coronary bypass surgery is dependent on graft patency after surgery. This trial was designed to determine if aspirin improved saphenous vein graft or internal mammary artery (IMA) graft patency between 1 and 3 years after coronary artery bypass grafting (CABG). METHODS AND RESULTS: After receiving aspirin 325 mg/d for 1 year after CABG and undergoing a 1-year postoperative cardiac catheterization, patients were randomized to receive either aspirin (325 mg) or placebo for 2 additional years. Angiography was performed 3 years after surgery to determine the primary end point-saphenous vein graft patency in 288 patients and IMA graft patency in 167 patients. At 3 years after CABG, the saphenous vein graft occlusion rate was 17.0% (62 of 365) for patients treated with aspirin compared with 19.7% (74 of 376) for those who received placebo (P = .404). For saphenous vein grafts that were patent at 1 year, the occlusion rate at 3 years was 4.8% (15 of 313) for patients treated with aspirin compared with 4.2% (13 of 310) for patients who received placebo (P = .757). At 3 years, the IMA graft occlusion rate was 10.3% (8 of 78) for patients treated with aspirin compared with 7.9% (7 of 89) for patients who received placebo (P = .594). For IMA grafts that were patent at 1 year, the occlusion rate was 4.3% (3 of 70) for patients treated with aspirin compared with 2.5% (2 of 81) for patients who received placebo (P = .541). CONCLUSIONS: These data suggest that aspirin treatment does not improve saphenous vein graft or IMA graft patency between 1 and 3 years after CABG.

Aspirin↗
PubMed1994

VA Study of Unstable Angina. 10-year results show duration of surgical advantage for patients with impaired ejection fraction.

BACKGROUND: In a randomized study of unstable angina, medically treated patients with impaired left ventricular (LV) ejection fractions (EF = 0.3 to 0.58) were at significantly higher risk of mortality than patients treated by coronary artery bypass graft surgery (CABG). Because the duration of this surgical advantage is unknown, 10-year cumulative mortality rates of patients with impaired LVEF were determined and compared with the previously observed rates at 2, 5, and 8 years. METHODS AND RESULTS: Of 468 patients with unstable angina, 237 were randomized to receive medical treatment alone and 231 patients to have CABG. Baseline characteristics, which were equally distributed between the two treatment groups, included age, LVEF, number of diseased coronary arteries, diabetes, clinical presentation (type I or type II), prior myocardial infarction, and smoking. Mortality was determined by life-table analysis and risk factors by logistic regression analysis. Patients were divided into terciles according to LVEF, and the mortality rates of medical and surgical patients in the lowest tercile were compared. The 10-year mortality rate for all medical patients was 38% and for all surgical patients, 39%. When LVEF was treated as a continuous variable, there was a significant relation between mortality and LVEF for medically treated patients but not for surgical patients. The cumulative mortality rate for the lowest-tercile (EF 0.3 to 0.58) medical patients was 49%; for the lowest-tercile surgical patients, 41% (P = .15). CONCLUSIONS: The surgical advantage for patients with impaired LVEF that was significant at 5 years (P = .03) and 8 years (P = .05) appears to have diminished at 10 years (P = .15).

Angina, Unstable↗
PubMed1993

Usefulness and tolerability of hirulog, a direct thrombin-inhibitor, in unstable angina pectoris.

In an open-label pilot study of 20 patients with unstable angina (Braunwald class I-IIIB), hirulog was administered as a continuous intravenous infusion for 5 days in a dose of 0.2 mg/kg/hour to produce an activated partial thromboplastin time of approximately 200% of control. The primary end points of the study were: death, development of a transmural myocardial infarction, and intractable angina needing interventions such as an intraaortic balloon pump insertion, angioplasty and surgery. The secondary end points were the presence of an intracoronary thrombus detected on angiography and hemorrhagic complications during therapy. There was no death or transmural infarction in this study cohort; however, 1 patient developed intractable angina. Intracoronary thrombus was documented in 2 patients. Infusion of hirulog resulted in a steady prolongation of the activated partial thromboplastin time without any hemorrhagic or other adverse effect. Hirulog appears to be an effective antithrombotic agent that is tolerated well and may have advantages over heparin in the management of patients with unstable angina.

Aged↗
PubMed1993

Pulmonary embolism after cardiac surgery.

OBJECTIVES: We examined the incidence of pulmonary embolism after cardiac surgery. BACKGROUND: Because venous thromboembolism is considered to be an uncommon complication after cardiac surgery, its incidence was documented in a consecutive series of 1,033 patients who underwent cardiac surgery over a 5-year period. METHODS: Parallel cohorts of patients in a tertiary referral center were evaluated and the incidence of pulmonary embolism was compared in subgroups of patients undergoing coronary bypass surgery, valve surgery and combined procedures. RESULTS: Pulmonary embolism developed in 33 (3.2%) of the 1,033 cardiac surgical patients, within 2 weeks of a coronary bypass operation in most; it did not develop in any patient who had isolated valve replacement surgery (p < 0.05). The diagnosis of pulmonary embolism was established by pulmonary angiography in 24 patients, ventilation/perfusion lung scan in 3, postmortem examination in 5 and clinical examination in 1 patient. Important risk factors for pulmonary embolism included prolonged postoperative recovery, obesity and hyperlipidemia. The mortality rate was 18.7% in patients with in contrast to 3.3% in those without pulmonary embolism (p < 0.01). CONCLUSIONS: Although pulmonary embolism is rare after isolated valve replacement, it is not an uncommon complication after coronary bypass surgery.

Aged↗
PubMed1992

Randomized trial of thrombolysis versus heparin in unstable angina.

BACKGROUND: The clinical usefulness of intravenous thrombolytic therapy in unstable angina is currently unknown, despite the pathogenetic similarity of this entity to acute myocardial infarction, for which thrombolysis has enjoyed great success. To compare the clinical benefit of intravenous urokinase with that of conventional antithrombotic therapy in preventing the progression of unstable angina to new myocardial infarction, intractable angina, or death within the first 96 hours after hospitalization, 149 patients with unstable angina were randomized to one of two intravenous thrombolytic strategies. METHODS AND RESULTS: Forty-nine patients received 3 million units urokinase i.v. over 90 minutes plus intravenous heparin (group A); 47 patients received unblinded 3 million units urokinase i.v. plus 325 mg aspirin p.o. daily (group B); and 53 patients received placebo thrombolytic infusion plus full-dose heparin (group C). The primary end point of this trial was 96-hour clinical status. There were no significant differences in the baseline characteristics (age, sex, previous myocardial infarction, hypertension prevalence, diabetes, tobacco use, or previous revascularization) among the three groups. Despite an excess of minor untoward reactions for the urokinase groups (chills, 26.5% and 23.4% for groups A and B versus 0% for group C; p < 0.01), there was no significant difference with respect to major bleeds (two, none, and two for groups A, B, and C, respectively; p = NS). At 96 hours after presentation, no significant difference emerged in the incidence of new cardiac events: new myocardial infarctions developed in 10.2% of group A, 6.4% of group B, and 3.8% of group C (p = NS); intractable angina occurred in 6.1% of group A, 10.6% of group B, and 9.4% of group C (p = NS). There were no deaths. All three groups encountered a similar incidence of overall cardiac events: 16.3%, 17.0%, and 13.2% for groups A, B, and C, respectively (p = NS). Although trial enrollment was to extend to 600 patients, interim analysis led to early cessation of enrollment due to a negative trend in respect to outcome after thrombolysis. CONCLUSIONS: High-dose intravenous urokinase followed by either heparin or aspirin can be safely administered to a broad, unselected group of patients with unstable angina. However, this study suggests that no clinical advantage is conferred by urokinase, with either adjunctive antithrombotic therapy over standard heparin therapy alone, when given relatively late (mean, 8.7 hours) after admission for unstable angina. A possible detrimental effect cannot be excluded.

Angina, Unstable↗
PubMed1992

Comparison of dosage schedules of rt-PA in the treatment of proximal deep vein thrombosis.

This study assessed the efficacy and safety of increasing durations of constant-dose intravenous recombinant tissue-type plasminogen activator (rt-PA) in the treatment of deep vein thrombosis. Patients with venogram-documented proximal lower limb (popliteal, iliofemoral) or upper limb (axillary, subclavian) thrombi were given an initial 2-hour rt-PA infusion at 4 micrograms/kg/min, followed by a maintenance infusion of 1 microgram/kg/min for an additional 4, 22, or 33 hours (mean total rt-PA dosages of 54, 127, and 185 mg). A new quantitative venogram scoring system was applied to the study, based on measurements of thrombus volume before and after completion of treatment. Whereas none of the seven patients given treatment for 6 hours and only one of four given treatment for 24 hours showed significant lysis, four of seven who received a prolonged infusion for 35 hours showed lysis of more than 40% of the original thrombus. Overall, the prolonged 35-hour infusion induced 51% lysis of original thrombus, representing a thrombus volume of 16.7 ml dissolved. Hemorrhagic complications were common in all three groups, with four of 18 patients having significant bleeding, including one massive gastrointestinal hemorrhage, two patients with a decrease in hematocrit of more than 10%, and one patient with an intracranial hemorrhage who recovered completely. Pharmacokinetics of the rt-PA showed a steady state antigen concentration of 240 ng/ml and activity of 200 IU/ml during the initial 2-hour infusion and a postinfusion half-life of 5 minutes. Plasma fibrinogen concentrations decreased to approximately 40% to 50% of initial values with all three treatment regimens, but the nadir fibrinogen concentrations did not correlate with either therapeutic efficacy or bleeding complications. One patient with systemic lupus erythematosus had an unusual allergic reaction that manifested primarily as angioedema. This study suggests that rt-PA infusion of 35 hours induces greater thrombolysis of deep vein thrombosis than does a shorter course of 6 or 24 hours, without an increase in hemorrhagic complications.

Adult↗
PubMed1991

Synthesis of glycuronamides of amino acids, constituents of microbial polysaccharides and their conversion into neoglycoconjugates of copolymer type.

Glycopyranosiduronic acids, amidically linked to amino acids (alanine, serine, threonine, and lysine) were prepared. O-tert-Butyl and N epsilon-tert-butyloxycarbonyl protected amino acid tert-butyl esters were used in ethyl 2-ethoxy-1,2-dihydroquinoline-1-carboxylate promoted condensation with 2-azidoethyl glycosides of glucuronic and galacturonic acid. Reduction of the azido-function followed by N-acryloylation and removal of blocking groups with trifluoroacetic acid gave the target monomers. These were converted into neoglycoconjugates of copolymer type, potentially useful for immunochemical studies.

Amides↗
PubMed1991

Starting aspirin therapy after operation. Effects on early graft patency. Department of Veterans Affairs Cooperative Study Group.

BACKGROUND: Although aspirin therapy started before operation improves vein graft patency after coronary artery bypass grafting, it also causes bleeding. The objective of this prospective, centrally directed, randomized, double-blind, placebo-controlled trial was to compare the effects of aspirin therapy started before operation with aspirin started 6 hours after operation on early (7-10-day) graft patency. METHODS AND RESULTS: Patients were randomized to receive either aspirin 325 mg or placebo the night before surgery; after operation, all patients received aspirin 325 mg daily, with the first dose administered through the nasogastric tube 6 hours after operation. Angiography was performed in 72% of the analyzed patients an average of 8 days after operation, and the primary end point was saphenous vein graft patency in 351 patients. Internal mammary artery graft patency was also assessed in 246 patients because many individuals received both internal mammary artery and vein grafts. In the patients given preoperative aspirin, the vein graft occlusion rate was 7.4 +/- 1.3% compared with 7.8 +/- 1.5% in those who received preoperative placebo (p = 0.871). In the subgroup of patients receiving Y grafts, 0.0% of the grafts were occluded in the preoperative aspirin group compared with 7.0 +/- 3.6% in the preoperative placebo group (p = 0.066). The internal mammary artery occlusion rate was 0.0% (0 of 131) in the aspirin group compared with 2.4 +/- 1.4% (three of 125) in the placebo group (p = 0.081). Patients in the aspirin group received more transfusions than those in the placebo group (median, 900 versus 725 ml, p = 0.006). The reoperation rate for bleeding in the aspirin group was 6.3% compared with 2.4% in the placebo group (p = 0.036). Median chest tube drainage within the first 6 hours after operation was 500 ml in the aspirin group compared with 448 ml in the placebo group (p = 0.011). CONCLUSIONS: Thus, preoperative aspirin is associated with increased bleeding complications and offers no additional benefit in early vein graft patency compared with starting aspirin therapy 6 hours after operation. There was a trend, although not significant, toward improved early patency for Y grafts and internal mammary artery grafts with preoperative aspirin.

Aged↗
PubMed1991

Coronary bypass surgery improves survival in high-risk unstable angina. Results of a Veterans Administration Cooperative study with an 8-year follow-up. Veterans Administration Unstable Angina Cooperative Study Group.

To identify high-risk subgroups, 468 patients with unstable angina were prospectively stratified according to the clinical presentation of unstable angina (type I or type II) and left ventricular function (normal or abnormal) and were randomized to conventional medical therapy or surgical treatment with coronary bypass surgery. Type I patients (n = 374) were those who had progressive effort angina or recent angina at rest. Type II patients (n = 94) were those who had severe rest angina associated with ST-T changes on the electrocardiogram. Follow-up for 8 years showed that the cumulative mortality rates for type II patients with abnormal left ventricular function were significantly lower in the surgical patients compared with the medical cohorts (13% versus 46%, p less than 0.04). In the other subgroups, cumulative medical and surgical mortality rates were not different. Thus, type II patients with abnormal left ventricular function appear to be the subgroup of patients who are at the highest risk with medical therapy. Coronary bypass surgery significantly reduces the mortality in this high-risk subgroup of patients with unstable angina.

Angina, Unstable↗
PubMed1990

Internal mammary artery and saphenous vein graft patency. Effects of aspirin.

As part of two Department of Veterans Affairs Cooperative Trials, we obtained angiographic patency data for internal mammary artery (IMA) and saphenous vein grafts to the left anterior descending (LAD) coronary artery at 1 year after coronary artery bypass surgery. Patients received either aspirin 325 mg q.d., aspirin 325 mg t.i.d., aspirin 325 mg and dipyridamole 75 mg t.i.d., or placebo. Aspirin was initiated either 12 hours before or 6 hours after operation. Patients were stratified preoperatively for extent of disease and randomized to the therapies outlined above. There was no randomization to IMA versus saphenous vein grafts to the LAD. When the patients taking placebo were compared with those taking aspirin, there were no differences in the IMA (100.0% versus 92.1%, p = 0.385) or vein graft (88.8% versus 90.4%, p = 0.675) patency rates. The patency rate, irrespective of treatment, for all IMA grafts was 92.8% (220 of 237) versus 90.1% (345 of 383) for all vein grafts to the LAD (p = 0.309). Thus, both the IMA and vein grafts had excellent patency rates at 1 year. Aspirin did not alter this at 1 year, and there were no differences between IMA and vein graft patency to the LAD.

Aspirin↗
PubMed1989

Medical compared with surgical management of unstable angina. 5-year mortality and morbidity in the Veterans Administration Study.

We evaluated medical in comparison to surgical plus medical (surgical) treatment of unstable angina using a prospective randomized protocol that stratified patients by clinical presentation and by invasive evaluation of left ventricular (LV) function. Clinical presentations were as follows--type 1: progressive or new onset angina relieved by medication; type 2: prolonged bouts of angina poorly or incompletely relieved by medication. Abnormal LV function was arbitrarily defined as ejection fraction less than 0.50 or LV end-diastolic pressure 16 mm Hg or more. Of 468 patients, 237 were assigned to medical and 231 to surgical therapy. There were 374 type 1 and 94 type 2 patients. LV function was normal in 334 and abnormal in 134 patients. Compared with results at 24 months, this 60-month follow-up study showed important differences in survival for patients with three-vessel disease: 75% for medical and 89% for surgical patients (p less than 0.02). The cumulative 5-year rate of repeat hospitalizations for cardiac reasons was less with surgical patients for either clinical presentation. For type 1, medical patients had a 56% rate, and surgical patients had a 42% rate (p = 0.004). For type 2, medical patients had a 62% rate, and surgical patients had a 43% rate (p = 0.05). Overall mortality did not differ between the two treatments, and this remained true in type 1 versus type 2 patients and in those with normal versus abnormal LV function. However, regression analysis of medical and surgical groups with ejection fraction as a continuous variable showed that mortality of medical patients depended on ejection fraction (p = 0.004), whereas the mortality of surgical patients did not (p = 0.76), and survival in the surgical group was higher in the lowest ejection fraction tercile-73% for medical and 86% for surgical patients, p = 0.03. We conclude that surgery improves survival in patients with three-vessel disease and leads to fewer subsequent hospitalizations for cardiac reasons. An impaired ejection fraction had an adverse impact on survival of medical patients but not on surgical patients, and mortality in surgical patients was improved compared with medical patients in the lowest ejection fraction tercile.

Angina Pectoris↗