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Biomedical subjects

S C Manchanda

Publications and source records attributed to S C Manchanda.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Apolipoprotein(a) polymorphism and its association with plasma lipoprotein(a) levels: a north Indian study.

Elevated levels of lipoprotein(a) has been regarded as an independent risk factor for coronary, peripheral and cerebral atherosclerosis. The enormous intra-personal variation in the plasma concentration of lipoprotein(a) is almost entirely controlled by the apolipoprotein(a) i.e. gene locus on the chromosome 6q 26-27. The apolipoprotein(a) molecule is highly polymorphic and is known to exist in multiple, genetically determined isoforms. These polymorphisms may be responsible for difference in promoter activity, variable size of apolipoprotein(a) and thereby variation in plasma lipoprotein(a) concentration. We studied the effect of two types of polymorphisms, (i) variation in length of the pentanucleotide repeat in the 5' flanking region starting -1373 bp upstream of AUG codon, and (ii) the Kringle-4 type 2 size polymorphism, on plasma lipoprotein(a) levels in North Indian population. The study group consisted of 88 angiographically assessed male coronary artery disease patients (age range 30-70 years) and 83 age- and sex-matched healthy controls. The pentanucleotide repeat polymorphism was analysed using polymerase chain reaction. In all, 8/11 pentanucleotide repeat isoforms were observed. Using SDS-agarose gel electrophoresis and immunoblotting isoforms having 12-50 Kringle-4 type 2 repeats were detected. Our study indicates a strong association of elevated plasma lipoprotein(a) concentration with coronary artery disease. An inverse correlation was seen between lipoprotein concentration and isoform size for both the pentanucleotide repeat polymorphism and the Kringle-4 type 2 polymorphisms; statistically significant difference (p = 0.001) was, however, observed only for the later.

Adult↗
PubMedDate not supplied

Two-catheter approach for ablation of accessory pathways in different locations.

Radiofrequency ablation is the treatment of choice for patients with Wolff-Parkinson-White syndrome and symptomatic tachyarrhythmias. The technique involves localising the pathway with multiple catheters at various sites followed by radiofrequency energy application at that site. Single catheter approach has been described for ablation of manifest left-sided accessory pathways. In this article, we report the ablation of accessory pathways in different locations in patients with Wolff-Parkinson-White syndrome by using a two-catheter approach. Twenty-three consecutive patients with symptomatic Wolff-Parkinson-White syndrome were taken up for radiofrequency ablation with this approach. Pathways could be successfully ablated in 11 out of 13 patients with left free wall, 5 out of 7 with right posteroseptal, one patient of left posteroseptal and each of the 2 patients of right mid septal locations giving an overall success in 19/23 (82.6%) patients. Hence, two-catheter approach can be used safely to ablate accessory pathways in different locations with high success rate, thus minimising the procedure time associated with conventional approach.

Adult↗
PubMedDate not supplied

Percutaneous transseptal mitral commissurotomy in pregnant women with critical mitral stenosis.

BACKGROUND: Percutaneous transseptal mitral commissurotomy has been successfully performed in selected pregnant patients with severe symptomatic mitral stenosis. Its safety and efficacy needs to be evaluated in a large number of cases. METHODS AND RESULTS: Percutaneous transseptal mitral commissurotomy was performed in 85 severely symptomatic (New York Heart Association functional class III or IV) pregnant women aged 22.7+/-4.1 years (range 18-39 years) with critical mitral stenosis at 24.8+/-4.7 weeks (range 20-34 weeks) of gestation. Percutaneous valvotomy was performed using a flow-guided Inoue balloon in all the patients. The procedure was considered successful in 80 (94%) patients. The hemodynamic mean end-diastolic gradient decreased from 26.7+/-6.8 mm Hg (range 16-35 mmHg) to 4.5+/-3.8 mmHg (range 0-14 mmHg) (p<0.001). The mean diastolic gradient decreased from 29.1+/-9.1 mmHg (range 18-38 mmHg) to 7.2+/-4.1 mmHg (range 4.1-18 mmHg) (p<0.001). The mean mitral valve area assessed by echocardiography increased from 0.75+/-0.5 cm2 (range 0.4-1.0 cm2) to 2.0+/-0.5 (range 1.0-2.7 cm2) (p<0.001). The mean fluoroscopy time was 3.6+/-3.2 minutes. The results of the mitral valvotomy were considered suboptimal in 4 patients. Mitral regurgitation increased by 1 grade in 16 patients and more than 2 grades in 2 patients. One patient developed pericardial tamponade during the procedure and was managed by catheter drainage. Percutaneous mitral valve dilatation was then successfully performed in this patient. No fetal abortion occurred after the procedure. CONCLUSIONS: The results of this study indicate that percutaneous transseptal mitral commissurotomy is a safe and effective procedure for severe symptomatic mitral stenosis in pregnancy.

Adolescent↗
PubMedDate not supplied

Coronary angiography using 4 French catheters with power injection: a randomized comparison with 6 French catheters.

BACKGROUND: Coronary angiography using 4 F catheters may reduce access-site complications and enable early ambulation, although earlier studies suggested that the quality of images may be an issue of concern. METHODS AND RESULTS: To ascertain the quality of angiographic images and safety of early ambulation, 500 patients were randomized to coronary angiography with either 4 F or 6 F catheters. Procedural characteristics, angiographic quality scores and results of ambulation were analyzed in the two groups. Patients in the 4 F group were mobilized at 2 hours post-procedure while those in the 6 F group were ambulated at 6 hours. There was no procedure-related complication in either group. The procedure was successfully completed in 250 of 252 patients randomized to the 4 F group. In two patients in the 4 F group, sheaths were upgraded to 6 F to complete the procedure, as difficulty was encountered in hooking the coronary ostium with a 4 F Judkin's catheter. Coronary angiographic quality scores in these two groups were comparable. Angiographic scores for the 4 F and 6 F groups for the left coronary artery averaged 4.45+/-0.5 and 4.58+/-0.3 (p>0.1), respectively. The right coronary artery scores averaged 4.30+/-0.4 and 4.35+/-0.2 (p>0.1) in the 4 F and 6 F groups. Angiographic scores for the left ventricular angiogram averaged 4.22+/-0.1 and 4.44+/-0.3 (p>0.1) in the 4 F and 6 F groups, respectively. None of the angiograms were assigned a score of <3.0 (not diagnostic). The total contrast volume consumed in the two groups was also equivalent. There were no groin-related complications in the 4 F group although these patients were ambulated 2 hours after the procedure. CONCLUSIONS: Coronary angiography performed with a 4 F catheter is a safe and reliable procedure. The quality of image obtained with a 4 F catheter is equivalent to that obtained with a 6 F catheter. Early ambulation at 2 hours is feasible without compromising safety.

Adult↗
PubMedDate not supplied

Restenosis after successful coronary angioplasty in single vessel disease.

One hundred and ninety five patients who underwent successful percutaneous transluminal coronary angioplasty (PTCA) for single vessel disease and have been followed up for more than 6 months are being reported. Angiography was done routinely in first 20 patients (Group 1) 8 to 15 weeks (mean 9.6 weeks) after PTCA. Restenosis (loss of 50% of the initial improvement in luminal diameter) was seen in 4 patients (20%). The remaining 175 patients (Group II) have been followed up clinically and subjected to serial exercise testing. Coronary angiography was performed only if symptoms and/or objective evidence of ischemia recurred. In this group, restenosis suspected clinically and confirmed by angiography occurred in 37 patients (21%), 2 to 23 weeks (mean 12.5 weeks) after PTCA. The restenosis rate for the entire patient population was 21%. In general the restenosed lesions were longer and tighter than the lesions before PTCA. A comparison of 41 patients with restenosis with those who did not have clinical restenosis revealed a proximal left anterior descending artery (LAD) involvement (66% vs 31%, p = 0.01), crescendo unstable angina (37% vs 16% p = 0.05), length of pre PTCA stenotic lesion greater than or equal to 1 cm (41% vs 27.5%, p less than 0.05), absence of intimal haziness in immediate post PTCA angiogram (27% vs 16%, p less than 0.05) and residual stenosis greater than or equal to 25%, (34% vs 14% p less than 0.05) in the restenosis group. Repeat PTCA was done in 30 patients with a 96% success rate; 4 patients required coronary artery bypass grafting (CABG). Restenosis after PTCA is a significant problem in our experience.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina, Unstable↗
PubMedDate not supplied

Coronary arteriographic profile in young and old Indian patients with ischaemic heart disease: a comparative study.

We analysed coronary arteriographic profile in 125 young patients (below 40 years, mean age 37.3 years) with clinical evidence of ischaemic heart disease (IHD) (Group I) and compared it with 125 older patients with IHD (more than 40 years, mean age 52.8 years) (Group II) studied during the same period. Left anterior descending coronary artery was the most frequently involved vessel in both the groups, 102/125 (81.6%) in Group I and 120/125 (96%) in Group II (P less than 0.001). The incidence of left main coronary artery involvement was 5/125 (4%) in Group I and 15/125 (12%) in Group II (P less than 0.05) and coronary artery calcification was 17/125 (13.7%) in Group I and 72/125 (57.6%) in Group II (P less than 0.001). Triple vessel disease was the most common form of involvement, 56/125 (44.8%) in Group I and 65/125 (52.8%) in Group II (P = NS). The incidence of diffuse disease was 35/125 (28%) in Group I vs 39/125 (31.2%) in Group II (P = NS), ectasia was observed in 13/125 (10.1%) in Group I vs 15/125 (12%) in Group II (P = NS) and coronary collaterals were found in 42/125 (33.6%) in Group I and 56/125 (44.8%) in Group II (P = NS). Thus left main and left anterior descending coronary artery disease and coronary calcification were more common in the older age group. Our findings suggest that in young Indian patients with IHD, multivessel and extensive coronary artery involvement in frequently seen. This pattern of involvement has many features resembling the disease pattern in their older counterparts.

Adult↗
PubMedDate not supplied

Clinical experience with low profile fixed wire balloon catheter system for percutaneous transluminal coronary angioplasty.

Clinical records of the first 45 consecutive patients (66 lesions) in whom the Probe TM a balloon on the wire, was used for percutaneous transluminal coronary angioplasty have been reviewed. The aim of this analysis was to establish the efficacy and safety of this device. Majority of the lesions taken up were considered severe and difficult to cross. The probe was the 1st catheter used in 51 lesions (77%) and in 15 lesions (23%) it was used after other balloon catheters. In 88% (58/66) of lesions treated the Probe reduced the stenosis to less than 50% of the luminal diameter. Of the 45 patients treated 39 (87%) had a successful result. Of the 19 patients with multiple lesions 74% (14/19) had complete revascularisation and in 16% (3/29) had the most significant vessel dilated. Two patients (3%) required urgent coronary artery bypass surgery for acute occlusions. There was no hospital death. Of 50 probe devices used 5 (10%) malfunctioned: the balloon ruptured (at 5 Bars pressure) in 2 instances, balloon twisted causing "Volvulous" in 1 and balloon failed to deflate in 2 cases. The probe has significant advantages over other balloon systems for treating severe coronary lesions because of its low profile. It is however a delicate catheter system and prone to malfunction if not handled with care. Our results show that it is an excellent system for opening difficult and tight coronary lesions.

Adult↗
PubMedDate not supplied

Contrastive effects of prostaglandin F2 alpha on normal cardiac rhythm and ouabain-induced cardiac arrhythmias in cats: possible neural basis.

The effects of prostaglandin F2 alpha (PGF2 alpha) on normal cardiac rhythm and ouabain-induced cardiac arrhythmias were investigated in chloralose-anaesthetized cats. PGF2 alpha (1-16 micrograms/kg i.v. bolus) produced ventricular arrhythmias and few incidences of AV conduction disturbances in normal cats. Changes in heart rate and blood pressure caused by PGF2 alpha in normal cats were complex, namely a decrease, an increase, or an initial decrease followed by an increase. Bilateral vagotomy antagonized the ventricular arrhythmias, AV conduction disturbances and hemodynamic changes produced by 16 micrograms/kg i.v. PGF2 alpha. On the other hand, atropine (2 mg/kg i.v.) pretreatment blocked the AV conduction disturbances and the reduction in heart rate and blood pressure, but not the ventricular arrhythmias or the increase in heart rate and blood pressure caused by 16 micrograms/kg i.v. PGF2 alpha. The ventricular arrhythmogenic effect of PGF2 alpha was prevented by propranolol (1 mg/kg i.v.). Intervention with cardiotoxic doses of ouabain augmented the PGF2 alpha-induced AV conduction disturbances, sinus bradycardia and hypotension, and attenuated the ventricular arrhythmias. Subsequent bilateral vagotomy prevented the ouabain-potentiated PGF2 alpha-induced AV block and sinus bradycardia, attenuated the hypotension and further reduced the ventricular arrhythmias. PGF2 alpha (2-16 micrograms/kg i.v.), contrary to its arrhythmogenic effect in normal cats, mainly suppressed ouabain-induced ventricular and supraventricular arrhythmias in ouabain-intoxicated cats, but aggravated the same in few cats. PGF2 alpha (16 micrograms/kg), prior to ouabain administration, produced ventricular arrhythmias in a group of 8 cats and later, in the same group of animals, when tested on ouabain-induced arrhythmias, it mainly antagonized them. These results suggest that PGF2 alpha evokes an arrhythmogenic effect on cardiac rhythm of normal hearts and mainly an antiarrhythmic effect on ouabain-induced arrhythmias largely through the mediation of two functionally opposing excitatory and inhibitory autonomic neural reflex pathways, respectively. The afferents of these pathways are of vagal origin. The efferent pathways of the inhibitory and excitatory reflexes involve in part increased vagal activity and increased sympathetic activity to the heart, respectively. Alteration by ouabain of the arrhythmogenic nature of PGF2 alpha on normal heart to its antiarrhythmic effect on the arrhythmic heart may be due to its selective potentiating effect on the inhibitory reflex pathway.

Anesthesia↗