Evolving coronary stent designs. Journey from substance to sublime.

Coronary artery disease continues to remain a global health care burden. Paradoxical changes in global economies have redefined future development and consumption markets. Within the next decade the need for high quality, low cost coronary stents may reach up to 10 million units. Parallel changes in technological trends further necessitate ingenuity in coronary stent development. Developing nations, armed with novel technologies, supported with low development costs and access to high end manufacturing are poised to serve the global demands of future coronary stent requirements. New concepts in DES engineering employing novel stent designs, drug delivery technologies and affordable DES systems will effectively bridge the need gap between metal backed DES and its ultimate nemesis the bioresorbable scaffold.

Consensus and development of document for management of stabilized acute decompensated heart failure with reduced ejection fraction in India.

AIM: Ensuring adherence to guideline-directed medical therapy (GDMT) is an effective strategy to reduce mortality and readmission rates for heart failure (HF). Use of a checklist is one of the best tools to ensure GDMT. The aim was to develop a consensus document with a robust checklist for stabilized acute decompensated HF patients with reduced ejection fraction. While there are multiple checklists available, an India-specific checklist that is easy to fill and validated by regional and national subject matter experts (SMEs) is required. METHODOLOGY: A total of 25 Cardiology SMEs who consented to participate from India discussed data from literature, current evidence, international guidelines and practical experiences in two national and four regional meetings. RESULTS: Recommendations included HF management, treatment optimization, and patient education. The checklist should be filled at four time points- (a) transition from intensive care unit to ward, (b) at discharge, (c) 1st follow-up and (d) subsequent follow-up. The checklist is the responsibility of the consultant or the treating physician which can be delegated to a junior resident or a trained HF nurse. CONCLUSION: This checklist will ensure GDMT, simplify transition of care and can be used by all doctors across India. Institutions, associations, and societies should recommend this checklist for adaptability in public and private hospital. Hospital administrations should roll out policy for adoption of checklist by ensuring patient files have the checklist at the time of discharge and encourage practice of filling it diligently during follow-up visits.

Accuracy of 64-slice CT coronary angiography: our initial experience.

OBJECTIVE: The objective of our study was to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography to detect haemodynamically significant stenosis (>50% luminal narrowing) in comparison to invasive coronary angiography and further analyze the result accounting for heart rate, coronary calcification and location of lesion in the coronary tree. METHODS AND RESULTS: Forty patients (39 male, 1 female; mean age 50.9 years) underwent both CT coronary angiography and invasive coronary angiography with in a gap of one day. All vessels were included in the study and no patient was excluded due to high heart rate. On per-segment based analysis with invasive coronary angiography as the gold standard, CT coronary angiography correctly identified 62 out of 78 significant stenoses with an overall sensitivity of 79.5% (62 of 78), specificity of 98.5% (532 of 540), positive predictive value of 88.6% (62 of 70) and negative predictive value of 97.1% (532 of 548). CONCLUSION: Our result suggests that 64-slice CT coronary angiography has high diagnostic accuracy to detect haemodynamically significant stenosis.

Very late stent thrombosis after implantation of drug eluting stent.

A case of late stent occlusion of a Sirolimus eluting Cypher stent (Cordis, Johnson and Johnson) presenting as acute ST elevation myocardial infarction 22 months after deployment is reported. The possible mechanisms are discussed.

Chronic atrial fibrillation in patients with rheumatic heart disease: mapping and radiofrequency ablation of flutter circuits seen at initiation after cardioversion.

BACKGROUND: There is little information concerning mapping and radiofrequency ablation (RFA) of arrhythmias seen during reinduction of atrial fibrillation (AF) after pharmacological and/or electrical cardioversion in patients with chronic AF and rheumatic heart disease. METHODS AND RESULTS: Seventeen patients with rheumatic heart disease and symptomatic chronic AF underwent multisite atrial mapping during reinduction of AF after cardioversion. An organized atrial arrhythmia of varying duration was seen to precede the AF in all patients. The earliest atrial activity during this organized rhythm was near the coronary sinus ostium (CS OS) in 14 patients and along the left side of the interatrial septum (IAS) in 3 patients. RFA was performed in 16 patients (14 near the CS OS and 2 along the IAS). Postablation AF was inducible in 1 patient in whom RFA was preformed near the CS OS and in both patients when it was performed along the IAS. At a follow-up of 6 to 56 weeks (mean, 32 weeks), 10 of the 13 patients who had successful ablation were in sinus rhythm. All patients in whom AF was reinducible immediately after RFA continue to be in AF. CONCLUSIONS: Induced AF in patients with rheumatic heart disease begins as a rapid organized arrhythmia with earliest atrial activity near the CS OS in most patients. RFA targeting the region of the CS OS is successful in suppressing the arrhythmia immediately in most of the patients and in most on follow-up.

Delayed occurrence of restenosis in drug eluting stents: an evidence of delayed healing.

Drug eluting stents have made a significant impact on restenosis. However, there are concerns regarding delayed "catch-up" of restenosis. In this case report we present two such patients with delayed occurrence of restenosis after drug eluting stent implantation.

Long-term follow-up after coronary stenting and intravascular red laser therapy.

A high restenosis rate remains a limiting factor for coronary angioplasty and stenting. Recently, use of intravascular red light therapy (IRLT) has been shown to be effective in different animal models and in humans in reducing the restenosis rate. Sixty-eight patients were treated with IRLT in conjunction with coronary stenting procedures. Mean age was 64 +/- 9 years. Treated lesions were type A (11), type B (42), and type C (18) with a mean lesion length of 16.5 +/- 2.4 mm. Reference vessel diameter and minimal lumen diameter (MLD) before therapy were 2.90 +/- 0.15 and 1.12 +/- 0.36 mm, respectively. After stenting and laser irradiation, MLD was 2.76 +/- 0.39 mm. No procedural complications or in-hospital adverse events occurred. All patients were followed up as depicted in the protocol. Sixty-one patients underwent angiographic restudy, which revealed restenosis in 9 patients (14.7%). Observed restenosis rate by artery size was > 3 mm (n = 21, 0%), 2.5 to 3.0 mm (n = 28, 14.2%), and <2.5 mm (n = 12, 41.6%). We conclude that IRLT is safe and feasible and reduces the expected restenosis rate in patients after coronary stenting in arteries of >2.5 mm.

Procedural results and early clinical outcome of percutaneous transluminal myocardial revascularization.

A substantial number of patients present with medically refractory angina who are not candidates for angioplasty or bypass surgery. The creation of channels between the myocardium and the ventricular blood pool has been performed after thoracotomy with excellent relief of symptoms but has been associated with high perioperative mortality. We investigated the safety of a nonoperative, percutaneous technique for channel creation. Twenty-seven patients with angina and coronary anatomy not amenable to revascularization with coronary angioplasty or bypass surgery underwent percutaneous transluminal myocardial revascularization (PTMR). Energy from a Holmium:yttrium-aluminum-garnet (YAG) laser was directed through a fiber enclosed in a catheter to the ventricular myocardium creating channels between the blood pool and the myocardium. On average, 17 +/- 4 channels were formed per patient. There were no procedure-related deaths, episodes of tamponade, or other complications except for an increase in creatine phosphokinase in 1 patient. Immediately after the procedure, there was no worsening of regional wall motion function in any patient, but rather improvement in some. All patients were discharged alive after a hospital stay of 1.8 +/- 1.5 days. Mean Canadian Cardiovascular Society functional class declined from 3.6 +/- 0.5 before the procedure to 0.65 +/- 0.8 at 30 days after the procedure (p < 0.01). For 12 patients eligible for 6-month follow-up, mean functional class was 0.94 +/- 0.97. At 6-month stress testing, 9 of these 12 had no electrocardiographic evidence of ischemia. Thus, PTMR can be performed safely in the cardiac catheterization laboratory with a complication rate lower than that reported in surgical series and with excellent near-term symptomatic relief. The long-term effect of PTMR on mortality and relief of angina as well as its safety and effectiveness compared with the surgical approach remains to be defined.

Fate of thrombectomized Björk-Shiley valves. A long-term cinefluoroscopic, echocardiographic, and hemodynamic evaluation.

Fourteen patients underwent thrombectomy for thrombosis of implanted Björk-Shiley valves (13 in the mitral and one in the aortic position) between January, 1975, and July, 1984. There was no operative mortality or perioperative embolism. Over a follow-up period of 1 to 96 months (average 23.5 months), there was no late mortality. Serial evaluation of valve function by cinefluoroscopy and echocardiography has shown no evidence of rethrombosis or valve dysfunction in any of the patients. Cardiac catheterization and angiocardiography done in 10 patients at various intervals (1 month to 6 years) postoperatively have shown normal valve function in all and normalization of elevated preoperative intracardiac pressures in the majority. Our experience suggests that thrombectomy of thrombosed Björk-Shiley valves provides excellent early and long-term results in terms of patient survival and valve function.

Digital subtraction venography for assessment of deep venous thrombosis in the arms following pacemaker implantation.

We recently performed digital subtraction venography and detected axillary venous thrombosis in a 56-year-old female with nonspecific symptoms related to the right arm following a permanent transvenous endocardial pacemaker implantation two years ago. In view of its cost-effectiveness and less invasive approach, digital venography appears ideally suited for evaluation of the frequently occurring subclinical deep venous thrombosis in these patients.

Unmasking of sinus node dysfunction by ajmaline.

A 75-year-old male with bifascicular block presented with recurrent giddiness and presyncope. Prolonged monitoring of the cardiac rhythm did not reveal any arrhythmia. Electrophysiological evaluation, including an ajmaline stress test, was performed. Ajmaline had an unusual effect. It reproducibly induced sinus arrest and thus unmasked a latent sick sinus syndrome.

Collateral circulation to the diagonal artery from the infundibular coronary artery in obstructive coronary arterial disease.

We report an unusual collateral pathway from the isolated infundibular (third coronary) artery to the diagonal artery in a young adult male with a history of recent anteroseptal myocardial infarction and apparently angiographically normal left and right coronary arteries. The isolated infundibular (conus) artery is an important source of collateral pathways in obstructive coronary arterial disease. Its selective arteriography is essential for complete angiographic evaluation of these patients.

Right atrial thrombus over eustachian valve--successful lysis with streptokinase.

Patients with pulmonary thromboembolism have occasionally been seen to have thrombi in the right atrium, either free floating or attached by a narrow pedicle. An echocardiographic description of a thrombus attached to the eustachian valve has, however, never been made in the literature. One such case is described in which streptokinase successfully lysed the thrombus.

Early intervention with propranolol after acute myocardial infarction: serial left ventricular function determined by M-mode and cross-sectional echocardiography.

Fifty patients (mean age 48.6 +/- 9.4 years) with uncomplicated acute myocardial infarction were randomly assigned to propranolol therapy (n = 25) or placebo (n = 25) in a double-blind manner within 24 hours of their presentation with acute symptoms. M-mode and cross-sectional echocardiography were performed at one week and three months to evaluate the left ventricular function. A comparison of the two groups revealed that the group receiving propranolol had higher left ventricular ejection fraction (69% vs 52%, P less than 0.001), fractional shortening (32% vs 24%, P less than 0.01), lower mitral E-point septal separation (6 mm vs 14 mm, P less than 0.001) and wall motion abnormality score (2.5 vs 6.0, P less than 0.001) than the group receiving placebo therapy. At three months there was further significant improvement in wall motion abnormality score (1.1 vs 2.5, P less than 0.001) in the propranolol-treated group as compared to the placebo group, whereas the other parameters remained unchanged. We conclude that the left ventricular function detected by M-mode and cross-sectional echocardiography showed significant improvement in patients with acute myocardial infarction after early intervention with propranolol. This is possibly due to a reduction in the size of infarction.

Myopotential inhibition of unipolar demand pacemakers: utility of provocative manoeuvres in assessment and management.

Fifty patients with permanent unipolar pacemakers (48 multiprogrammable, 2 non programmable) with protective insulating sheath placed against the muscular side of the pacemaker pocket were studied to determine the occurrence of inhibition of pacing by sensing of the myopotentials. All the patients were subjected to a combination of different provocative manoeuvres at their nominal R wave sensitivity settings. Myopotential inhibition was exhibited in 35 (70%) patients. Only 3 patients however had reported symptoms suggesting loss of pacing. The most useful provocative manoeuvre was shoulder flexion with adduction against resistance (94.3% positivity). Appropriate sensitivity adjustments resulted in amelioration of the problem in 86% of the patients while still retaining R wave sensing. Myopotential interference continues to be a frequently observed problem even in the present generation of unipolar pacemakers. Provocative tests and appropriate reprogramming should be done in all such patients as a routine.

Effects of labetalol on left ventricular mass and function in hypertension--an assessment by serial echocardiography.

We determined echocardiographic (M-mode) indices of left ventricular mass and function serially at 1-month intervals in 10 patients with uncomplicated mild or moderate essential hypertension, before and after adequate control of blood pressure with labetalol, a combined alpha- and beta-receptor blocking agent. Seven patients had pretreatment echocardiographic evidence of left ventricular hypertrophy with disproportionate septal thickness in 4. Systolic blood pressure in the untreated state correlated well (r = 0.96) with left ventricular mass but poorly (r = 0.30) with diastolic pressure. Following a satisfactory blood pressure reduction, achieved in all patients, left ventricular mass decreased from 240.5 +/- 71.1 g to 159.5 +/- 40.7 g (P less than 0.01), interventricular septal thickness from 1.33 +/- 0.3 cm to 0.92 +/- 0.25 cm (P less than 0.01) and posterior wall thickness from 1.03 +/- 0.23 cm to 0.93 +/- 0.23 cm (P less than 0.05). While the maximum changes in left ventricular mass were noted by the end of first month (P less than 0.01) with insignificant changes thereafter, the correlation of fall in blood pressure with change in left ventricular mass was significant only after 2 months of treatment (P less than 0.05). Indices of left ventricular function (end-diastolic volume, ejection fraction, fractional diameter shortening, left atrial dimension and posterior aortic wall motion) were normal before treatment and remained unchanged during 3 months of treatment. In this short-term study, labetalol reduced left ventricular hypertrophy (expressed as left ventricular mass and wall thickness) without altering left ventricular function indices in patients with uncomplicated essential hypertension. This has important implications in the treatment of hypertensive patients.

The morphology of coronary arterial dissection occurring subsequent to angioplasty and its influence on acute complications.

We reviewed the records of 402 patients undergoing percutaneous transluminal coronary angioplasty to identify factors predicting an ischemic event with arterial disruption during an otherwise uncomplicated angioplasty. Major dissection of the coronary arteries without immediate occlusion was found in 25 patients, who exhibited 28 dissected lesions. Dissections were classified into 2 types: those producing a continuous extraluminal and parallel filling tract, and those with a continuous parallel filling tract extending into and compromising the lumen. Ischemic complications (defined as myocardial infarction, the need for repeat angioplasty, or coronary arterial bypass surgery) occurred in 6 patients (24%) within 24 hours of the completion of the procedure. The remaining 19 patients had an uncomplicated hospital course. Acute ischemic complications following dissection correlated with the percentage of luminal compromise 50 +/- 0% in those with complications as opposed to 17 +/- 21% in those without: P less than 0.001) and the development of dissection producing a filling tract which compromised at least half the lumen (100% in those with complications versus 9.1% in those without: P less than 0.001). There was a trend towards an increase in ischemic complications in patients with proximal and eccentric lesions. We conclude that patients who develop dissections which produce significant luminal compromise after an otherwise uncomplicated angioplasty are at a high risk of developing an acute ischemic complication within 24 hours of the procedure.

Significance of advanced atrioventricular block in acute inferior myocardial infarction--a study based on ventricular function and Holter monitoring.

Eighty-two consecutive patients with a first inferior wall acute myocardial infarction were evaluated by radionuclide angiography and 24-hour Holter monitoring during their hospital stay. The patients were divided into two groups. The first group (n = 28) had advanced atrioventricular block, while the second group (n = 54) were without atrioventricular block. The patients with advanced block had lower left ventricular (49 +/- 12% vs. 55 +/- 14%, P less than 0.05) and right ventricular ejection fraction (26 +/- 10% vs. 43 +/- 11%, P less than 0.001) than those with normal atrioventricular conduction. The atrioventricular block disappeared spontaneously in all of them. The hospital mortality of the patients with advanced block and those without advanced block was 10.7 and 5.5%, respectively (P = NS). Pre-discharge 24-hour Holter monitoring done in all survivors revealed isolated ventricular ectopics (Lown grade I, II, III) in 44% of patients who had had advanced block and 43.1% of patients without advanced block (P = NS). Complex ventricular ectopics (Lown grade IVa, IVb), however, were recorded in significantly more patients with advanced block as compared to patients without advanced block (36 vs. 7.8%, P less than 0.01). Most patients with complex ventricular ectopics in both groups had impaired left or right ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

The value of intracardiac electrophysiologic techniques in recurrent syncope of "unknown cause".

We prospectively evaluated and followed-up 45 patients with syncope in whom conventional cardiovascular and neurological investigations did not reveal the cause. All patients underwent electrophysiologic studies to assess the function of the sinus node and the integrity of atrioventricular conduction. These included the ajmaline test and the inducibility of supraventricular or ventricular tachycardia. Seven patients (15.5%) had evidence of sinus node dysfunction, 8 patients (17.7%) had evidence of infra-His atrioventricular block after ajmaline administration and 5 patients (11.1%) had inducible ventricular tachycardia. The remaining 25 patients (55.5%) had non-diagnostic studies. All patients with sinus node dysfunction and inducible infra-His atrioventricular block were asymptomatic during a mean follow-up period of 14.3 +/- 9.5 months after implantation of a permanent pacemaker. Patients with inducible ventricular tachycardia (except 1 with poor left ventricular function who died) were likewise asymptomatic while receiving laboratory guided anti-arrhythmic drug therapy. Twenty-five patients with non-diagnostic studies who were treated empirically are alive but the symptoms persist in 14 (56%). Provocative electrophysiological studies are of diagnostic and therapeutic utility in a significant number of patients with recurrent syncope of "unknown cause".