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Biomedical subjects

M Nair

Publications and source records attributed to M Nair.

86 records · Page 5Linked to original sources
PubMedDate not supplied

Detection of multivessel coronary artery disease by early exercise testing after first myocardial infarction.

The ability of a symptom limited treadmill exercise test (TMT) to predict the presence of multivessel coronary artery disease (MVD) three weeks after a first myocardial infarction was assessed in 76 male patients aged 25-65 (mean 40.9 +/- 10.1) years. There were 6 patients with normal coronaries, 36 with single vessel disease (SVD), 20 with double vessel disease (DVD), and 14 with three vessel disease (TVD). TMT was positive in 20/34 (58.8%) patients with MVD, and 4/42 (9%) patients with SVD or normal coronaries. The predictive accuracy of a positive TMT in detecting MVD was 83.3%, and the predictive accuracy of a negative TMT in excluding MVD was 73.1%. It is concluded that TMT is useful test for predicting the presence or absence of MVD in survivors of a first transmural myocardial infarction.

Adult↗
PubMedDate not supplied

Coronary angioplasty of 'complex lesions' in patients with unstable angina.

Out of 55 patients subjected to coronary angioplasty over the past 12 months, there were 33 (60%) who had unstable angina. Amongst these, 22 patients had coronary lesions classified as 'complex' on coronary angiography. These included tandem lesions, branch stenoses, distal lesions, total occlusions, vein graft stenoses, lesions with ulceration and intraluminal clot and associated with valvular lesions. We describe our experience of coronary angioplasty in these 22 patients of unstable angina having 'complex lesions'. All were males with a mean age of 48.7 +/- 13 years. Fourteen patients had single vessel and 8 multivessel disease. A total of 35 lesions were subjected to dilatation. The angiographic primary success was achieved in 85.7% of the lesions attempted. Except total occlusions and very distal lesions, all other types of 'complex lesions' could be dilated with a success rate of greater than 75%. There were 4 (11.4%) failures because of inability to cross the lesion with the guidewire or balloon catheter. One patient developed non-Q wave inferior wall infarction. There were no deaths. We conclude that coronary angioplasty of various types of 'complex lesions' can be performed with a good primary success and negligible complications in our setting.

Adult↗
PubMedDate not supplied

Clinical, angiographic and histopathological predictors of restenosis after directional coronary atherectomy.

Out of 127 directional coronary atherectomy (DCA) procedures done in our laboratory, there were 81 patients who had completed a minimum of six months of follow-up. To study the factors predisposing restenosis after successful DCA, we analysed the clinical and angiographic profile of the patients and the histopathological findings of the excised tissue in 44 patients whose complete follow-up data was available with us. The indication of DCA was an extremely eccentric significant stenosis located in the proximal or midsegment of a large vessel (> or = 3 mm size) in 97 percent of the cases. Angiographic restenosis, defined as more than 50 percent luminal diameter stenosis was absent in 24 (54.5%, Group A) and present in 20 (45.5%, Group B) patients. On univariate analysis, the factors which predisposed to restenosis were: (i) left anterior descending location, (ii) longer lesion length (9.6 +/- 3.1 mm vs 5.2 +/- 1.6, p < 0.01) and (iii) greater post-procedure residual luminal diameter stenosis (13.1 +/- 10.8% vs 4.3 +/- 6%, p < 0.01). No significant difference was found between the two groups for other variables like unstable angina, the location and the morphological characteristics of the lesion and the ratio of the vessel diameter to the size of the Atherocath. Histopathological examination of the retrieved tissue revealed the presence of media with or without external elastic lamina in 8 (33%) patients in Group A--without restenosis compared to only 1 (5%) patients in Group B--with restenosis (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Atherectomy, Coronary↗
PubMedDate not supplied

Directional atherectomy for the dilatation of bifurcation stenoses in the coronary arteries.

Although bifurcation lesions in the coronary arteries can be dilated with balloon angioplasty, directional atherectomy is emerging as the treatment of choice in patients with large arteries. In this study, we report the immediate results and acute complications of treating bifurcation lesions in the coronary arteries with directional atherectomy in 9 patients, ranging in age from 33 to 60 (mean 56.7 +/- 10.8) years. All patients had true bifurcation stenoses with luminal diameter narrowing of more than 70 percent in both the primary vessel and the side branch. The lesions involved the left anterior descending (LAD)-diagonal system in 5, left circumflex (LCx)-obtuse marginal (OM) in 2, distal right coronary artery (RCA) in 1 and bifurcation of a large first diagonal branch in one patient. Double-wire atherectomy technique was used in 4 patients, although 7 had an additional wire in the side branch during post-atherectomy balloon angioplasty. The procedure was successful in all patients (100%), with luminal diameter stenosis decreasing from 93 +/- 7.5 percent to 6 +/- 8.6 percent in the primary vessel and from 83 +/- 9.2 percent to 13 +/- 9 percent in the side branch. There were no major complications. Minor complications included non-flow limiting dissection in 4 patients, distal migration of thrombus in one, occlusion of 2 small distal branches of the diagonal in one and entwinement of the guidewires in one. In conclusion, directional atherectomy can be performed safely and successfully for dilatation of complex bifurcation lesions in the coronary arteries without any major complications using the double-wire or sequential atherectomy technique.

Adult↗
PubMedDate not supplied

Comparison of electrophysiologic effects and efficacy of single-dose intravenous and long-term oral amiodarone therapy in patients with AV nodal reentrant tachycardia.

Electrophysiologic effects and the efficacy of single-dose intravenous (i.v.) amiodarone were compared with those of long-term oral therapy in 9 patients of AV nodal reentrant tachycardia (AVNRT) utilising slow pathway (SP) for anterograde and fast pathway (FP) for retrograde conduction. Electrophysiologic data were obtained by programmed electrical stimulation (PES) before, 15 to 30 minutes after i.v. amiodarone (5 mg/kg body-weight over 10 minutes) and a mean of 64.6 +/- 23.7 days after oral therapy, on a maintenance dose of 200 to 400 mg daily. There was no significant influence on the sinus cycle length and infranodal conduction (HV) by i.v. or oral amiodarone as compared to pre-drug values. AV nodal conduction, evaluated by AH interval, increased significantly and comparably with both (8% after i.v., 10% after oral; p = NS). Anterograde conduction through SP, as evidenced by pacing cycle length producing AH block, was prolonged by both (31% after i.v., 52% after oral; p = NS). Oral amiodarone, however, was more effective than i.v. in lengthening the effective refractory period (ERP) of anterograde FP (45% vs 17%, p < 0.05). Although both depressed retrograde conduction significantly, long-term oral amiodarone was more effective in prolonging the paced cycle length (PCL) producing ventriculoatrial (VA) block (79% vs 50%; p < 0.05) and ERP of VA conduction system (72% vs 42%; p < 0.01). AVNRT was successfully terminated in 7 patients after i.v. amiodarone. However, tachycardia was reinducible in 3 patients after i.v. and in none after long-term oral therapy. None had clinical recurrence of tachycardia on maintenance oral therapy. The mean concentration of the drug was 3.1 +/- 1.81 micrograms/ml after i.v. and 1.3 +/- 0.47 micrograms/ml after oral therapy (p < 0.05). These results. suggest that i.v. amiodarone terminated AVNRT by depressing both anterograde and retrograde limbs of the reentrant circuit and eventually blocking one of these. Oral therapy prevented recurrence and reinducibility by its predominant effect in prolonging refractoriness of the atrium and ventricle, and depressing conduction through the retrograde FP. It is concluded that i.v. amiodarone is an effective drug in acute termination of tachycardia mediated by AV nodal reentry and that long-term oral therapy is excellent in preventing recurrence and reinducibility of tachycardia. There are significant differences in the electrophysiologic properties and mechanism of action between the two forms, not influenced by the blood levels of amiodarone.

Administration, Oral↗
PubMedDate not supplied

Ischaemic stroke in the young adult: clinical features, risk factors and outcome.

BACKGROUND: Stroke is an important cause of morbidity and mortality in young adults, especially in developing countries. This study aimed to evaluate the clinical features, risk factors and outcome of ischaemic stroke in young adults aged 15-45 years. METHODS: A retrospective review was done of the medical records of 177 patients seen in a tertiary referral centre in Thiruvananthapuram, Kerala between January 1988 and March 1994. RESULTS: There were 135 males and 42 females with a mean (SD) age of 34.7 (8) years at onset of stroke. An aetiological categorization of stroke was obtained in 111 (63%) patients and it was uncertain or unknown in the rest. Athero-thrombotic stroke and cardio-embolic stroke occurred in 24% and 17%, respectively. Hypertension, smoking, hyperlipidaemia and athero-thrombotic stroke were significantly more prevalent in the 31-45 year age group compared to the 15-30 year age group. There was only one patient with postpartum intracranial sinovenous thrombosis. At a mean follow up of 7 months (range 1-62 months), 75% of the patients were independent or only mildly disabled. The case-fatality rate was 1%. CONCLUSION: Ischaemic stroke in the young adult is more frequent in males. The aetiopathogenesis can be determined in the majority and the athero-thrombotic process predominates. The mortality is negligible and the functional outcome is good in most patients.

Adolescent↗
PubMedDate not supplied

Coronary artery stenting for isolated proximal left anterior descending stenosis: immediate and follow-up results.

Between February 1995 to August 1997, 120 patients underwent elective stent implantation for isolated proximal left anterior descending coronary artery stenosis. Their age ranged from 31 to 72 years (mean: 50.8 +/- 10.2) and the majority (89%) were males. All patients had angina, documented myocardial ischemia or both and 70 percent or more luminal diameter stenosis in the proximal left anterior descending before the origin of any branch. Majority (62.5%) of the treated lesions were type A. Successful deployment of the stent at the target site was achieved in all patients without any major in-hospital complications, including myocardial infarction, emergency bypass graft surgery or death. Clinical follow-up, ranging from 6 to 31 months (mean: 18.5 +/- 8.1, median: 20), was available in 87 out of 92 (94.5%) eligible patients who had completed at least six months after the procedure. Freedom from angina, myocardial infarction, target lesion revascularization and death was observed in 90.8, 100, 95.4 and 97.7 percent of patients, respectively. By the Kaplan-Meier estimate, an event-free survival (absence of death, myocardial infarction, recurrence of angina or revascularization) was 95.4 percent at six months, 89.5 percent at 12 and 18 months and 82.7 percent at 24 to 31 months of follow-up. Only 10 (11.5%) patients developed any event and TLR was required in 4.6 percent of patients. In conclusion, elective stenting for isolated proximal left anterior descending stenosis can be achieved safely and successfully in all patients without any adverse in-hospital events. This modality of treatment also provides long-term benefits in terms of reduction in major cardiovascular events and need for subsequent revascularization.

Adult↗