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Biomedical subjects

V K Mehan

Publications and source records attributed to V K Mehan.

At least 19 recordsLinked to original sources

Stenting with the half (disarticulated) Palmaz-Schatz stent.

A total of 110 half (disarticulated) Palmaz-Schatz coronary stents were implanted in 102 patients. Procedural success rate was 98%. Elective stenting was performed in five patients. The others received half stents for bail-out situations, including short dissections, relapsing stenoses, dissections not adequately covered by a full stent, ostial stenoses, and thrombus containing lesions. Seventeen patients received no anticoagulation except aspirin. Complications included one procedural death, three acute occlusions (resulting in one Q and two non-Q wave myocardial infarctions), and one non-Q wave infarction related to side branch closure. Stenting with the half Plamaz-Schatz coronary stent is an effective technique. It allows stenting in situations where a full stent may not be ideally suited. Use of only half a stent reduces thrombogenicity and halves costs.

Adult↗

Coronary stenting without anticoagulation.

Stents are useful bail-out devices in coronary angioplasty. They are also used electively for situations associated with poor angioplasty results (e.g., restenotic lesions, venous grafts) and may reduce restenosis rates. However, the significant incidence of stent thrombosis necessitated aggressive anticoagulation with associated hemorrhagic complications. This remains a major limitation of stenting. We present our experience of stenting with half (disarticulated) Palmaz-Schatz coronary stents in eight consecutive patients, managed with aspirin alone. No patient experienced acute or subacute stent thrombosis.

Adult↗

Coronary angioplasty for isolated non-dominant left circumflex coronary artery disease.

The study describes the clinical findings and results of coronary balloon angioplasty in 134 patients with non-dominant left circumflex coronary artery disease. The immediate angiographic success rate was 97% versus 95% for left anterior descending (P = NS), and 90% for right coronary lesions (P < 0.002). There was no hospital mortality in the circumflex group versus 1.2% in the left anterior descending (P < 0.01), and 0.4% in the right coronary artery group (P = NS). Major non-fatal cardiac complications were significantly lower in the non-dominant left circumflex coronary artery patients (no new Q-wave versus 3% in the left anterior descending, P < 0.0002, and 3% in the right coronary artery group, P < 0.01; no urgent coronary artery bypass grafting versus 2% in the left anterior descending, P < 0.001, and 1% in the right coronary artery group, P = NS). The freedom from chest pain was 63% in 112 patients (84%) with follow-up data available at 24 +/- 18 months, and mean angina class diminished to 0.7 +/- 1.3 (P < 0.001). Consumption of antianginal and other cardiac drugs was diminished during follow-up, and the number of patients on no such drugs increased from 5 to 32% (P < 0.001). Restenosis was found in 19 of 32 patients with repeat coronary angiography (59%). Repeat angioplasty was required in 22 patients during follow-up and in 4 of them (18%) it was done for new lesions. Angioplasty for isolated non-dominant left circumflex coronary artery disease yields excellent immediate and long-term results.

Angioplasty, Balloon, Coronary↗

Interventional cardiology: state of the art.

Since the advent of percutaneous transluminal coronary angioplasty (PCTA) in 1977, a new breed of cardiologists was born "Interventional Cardiologists". To date, a wide range of new interventions have been developed including percutaneous closure of atrial septal defects and balloon dilatation of the pulmonary valve and mitral valvuloplasty among others. In 1994, the final position of interventional cardiology is not fully defined but indicates what can be expected in the near future. Conventional coronary angioplasty presently accounts for over 90% of all coronary interventions and is likely to remain the cornerstone of coronary interventions. New techniques include stents which have been shown to be effective in acute and threatening occlusions as part of the armamentarium against restenosis. The Rotablator is a technique which uses an olive-shaped high-speed burr coated with diamond chips used for debulking lesions though to represent a high risk/low success rate for balloon angioplasty. Directional coronary atherectomy, transluminal extraction catheters, and Rotacs (a low-speed rotator) have also been developed. Laser angioplasty, which initially created great enthusiasm, probably will be of limited use. Mitral balloon valvuloplasty has emerged as the most common balloon valvuloplasty performed world-wide. It can be performed with or without fluoroscopy, particularly useful in pregnant women. Balloon valvuloplasty is also the treatment of choice in cases of pulmonary stenosis and balloon dilatation of the aortic valve, initially developed for children is now indicated in adults with the exception of elderly patients with calcified valves for whom valve replacement is indicated. Other interventions currently performed include balloon angioplasty for aortic coarctation following surgical repair and transcatheter closure of shunts. Patent ductus arteriosus, atrial septal defect and ventricular septal defect are choice indications. Certain congenital heart diseases including the creation of atrial septal defects in neonates whose survival depends on such a shunt and the treatment of pulmonary branch stenosis, venous obstructions, discrete subaortic stenoses and dilatation of the infundibular stenosis. Coil embolization of arteriovenous fistulae has also been developed. Finally, ablative techniques of invasive electrophysiology have further widened the indications of interventional techniques in cardiology which will continue to develop as an important pole of research and clinical applications in the future.

Angioplasty, Balloon↗

Use of half (disarticulated) Palmaz-Schatz stents for thrombus-containing coronary lesions.

Coronary stenoses associated with thrombus can lead to poor angioplasty results and increased procedural complications. Stenting in the presence of thrombus is associated with an increased risk of stent thrombosis. We report eight patients in whom half a Palmaz-Schatz stent was implanted for inadequate angioplasty results owing to thrombus. Stenting resulted in improved angioplasty results; no stent thrombosis occurred.

Angioplasty, Balloon, Coronary↗

Coronary angioplasty through 4 French diagnostic catheters.

In 50 consecutive patients subjected to coronary angioplasty immediately following a 4 French (F) diagnostic study, the technical feasibility and economical aspects of angioplasty through 4F catheters of 54 lesions were assessed. The patients were selected, but multiple, eccentric, and long lesions were not a priori excluded. 4F diagnostic catheters (Cordis), and fixed-wire dilatation catheters (Ace, Scimed) were used in all cases. The procedure was successful in 43 lesions (80%) using 4F catheters. For 11 stenoses (20%), a change over to a larger French size was required. Two of these lesions could not be crossed with the balloon despite the larger sized guiding catheter. The final overall success rate was 96%, and there were no major complications. The use of diagnostic 4F catheters for angioplasty in these 50 patients resulted in the saving of 39 guiding catheters and 19 introducer sheaths. For 12 lesions (22%), an additional 4F catheter became necessary since the shape used for the diagnostic study was inadequate for angioplasty. In 7 cases, more than 1 balloon was used, but 5 of these balloon exchanges were independent of the use of 4F catheters. Three exchanges were performed through the 4F catheter (1 for need of a larger balloon to improve on an unsatisfactory angiographic result and 2 for a crimped guide wire tip of the Ace balloon). In the remaining 4, a larger catheter was used; in 2 of them, angioplasty eventually failed (failure to cross lesion) and in the remaining 2, a Monorail system solved the problem, which is incompatible with 4F catheters.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

Conventional coronary angioplasty.

Coronary angioplasty has come a long way since its inception 16 years ago. Although several new devices have shown promise, none, with the exception of the stent, has significantly changed results, and the "simple" balloon remains the backbone of coronary angioplasty. Increased operator experience and advanced guidewire and balloon technology have expanded indications for the procedure to include multivessel angioplasty, angioplasty of chronic occlusions and grafts, angioplasty in the setting of acute myocardial infarction, and supported, high-risk angioplasty. However, single-vessel angioplasty remains by far the most common form of this procedure. Restenosis continues to be an unsolved problem. Results of several trials comparing angioplasty and surgery are expected soon, but they will not answer the question of which method of revascularization is best for the individual patient.

Angioplasty, Balloon, Coronary↗

Streptokinase treatment of a thrombosed Björk-Shiley prosthesis in the aortic position.

Dysfunction of a mechanical prosthetic valve caused by thrombus formation is usually treated surgically. A patient with a thrombosed Björk-Shiley valve in the aortic position was treated successfully with intravenous streptokinase. The considerable improvement in the patient's clinical condition and the phonocardiographic, echocardiographic, and cinefluoroscopic evidence of normalisation of prosthetic valve function established the efficacy of thrombolytic therapy of a thrombosed prosthetic valve in this patient.

Adult↗

PTCA at first sight: angioplasty based on video only.

The results of 326 coronary angioplasties (PTCAs) performed during a first diagnostic angiography and based on video images only (PTCA at first sight, Group I) are compared with those of 756 PTCAs done during the same time period in patients with a previous cine-film and therefore a known or predictable coronary anatomy (Group II). Group I patients had more single vessel disease (74% versus 58%, p less than 0.001), single vessel PTCA (93% versus 84%, p<0.001), unstable angina (54% versus 28%, p less than 0.001), recent myocardial infarction (66% versus 37%, p less than 0.001), and total occlusion PTCA (29% versus 19%, p<0.01). On the other hand, they had less severe stable angina (mean New York Heart Association class 1.3+/-1.2 versus 1.8+/-1.4, p less than 0.001), less advanced disease (average of 1.3+/-0.5 versus 1.5+/-0.7 diseased vessels, p less than 0.001) and worse left ventricular ejection fraction (61+/-12% versus 63+/-12%, p less than 0.01). The angiographic and clinical success rates were 90% and 84% in Group I and 92% and 87% in Group II respectively, (p=NS). Complication rates were not statistically different between the groups (Q-wave myocardial infarction 2% versus 3%, non Q-wave myocardial infarction 4% in both groups, emergency surgery 0.3% versus 0.8% and inhospital mortality 0.9% for both groups). In selected patients, coronary angioplasty can be performed safely and effectively during a first coronary angiography based on video images exclusively.

Adult↗