Cardiophile MD

3D quantitative coronary angiography

Johnson Francis — Mon, 20 Feb 2012 05:59:43 +0000

Conventional coronary angiography is a two dimensional visualization of coronary anatomy. There are inherent limitations to this like foreshortening which results from angiographic views which are not perpendicular to coronary segments being visualized. This is taken care of by taking multiple orthogonal views so that significance of a lesion is not missed by foreshortening in one view. Various three dimensional (3D) reconstruction softwares have been developed to overcome this problem. But these have not become part of routine coronary angiographic practice unlike in neuro imaging where 3D reconstruction of cerebral angiography is routine practice and has been built into modern angiographic equipment. This is mainly due to limitation in case of coronary imaging due to the constant motion as a result cardiac action where as cerebral vessels are relatively immobile and allows easy 3D reconstruction during a single shot of rotational angiography with automatic delivery of contrast and gantry rotation. One of the software systems for 3D coronary imaging (CardiOp-B) has real time and off line analysis with 3D reconstruction using all the information from two 2D angiograms into one 3D image [Gradaus R et al. Clinical assessment of a new real time 3D quantitative coronary angiography system: evaluation in stented vessel segments. Catheter Cardiovasc Interv. 2006;68:44-9]. This system derived measurements correlated well with predefined measures of stents at designated inflation pressures. Another study compared 3D imaging system with intravascular ultrasound (IVUS) measurements [Tu S et al. A novel three-dimensional quantitative coronary angiography system: In-vivo comparison with intravascular ultrasound for assessing arterial segment length. Catheter Cardiovasc Interv. 2010;76:291-8]. They could demonstrate good correlation between IVUS derived measurements and 3D angiographic measurements.

Myocardial contrast delayed enhancement with 64-slice multidetector CT after acute MI

Johnson Francis — Fri, 17 Feb 2012 15:12:13 +0000

Sato A et al have assessed the role of myocardial contrast delayed enhancement with 64-slice multidetector computerized tomography (MDCT) after acute myocardial infarction (MI) in prediction of clinical outcome [Prognostic Value of Myocardial Contrast Delayed Enhancement With 64-Slice Multidetector Computed Tomography After Acute Myocardial Infarction. J Am Coll Cardiol, 2012; 59:730-738]. Among the 102 patients, nine died and twelve had heart failure during the study period. The size of delayed enhancement on myocardial contrast CT was found to be a significant independent predictor for cardiac events after adjustment for TIMI (Thrombolysis In Myocardial Infarction) risk score, left ventricular ejection fraction and total defect score on technetium scan. The study was performed immediately after successful percutaneous coronary intervention (PCI). MDCT was performed immediately after the final check angio of PCI procedure without administering any further contrast for the CT. Repeat angiograms were performed at six months after the PCI. Infarct area was defined as a hyperenhancement with a signal intensity higher than two standard deviations above the mean signal intensity of normal myocardium remote from the infarct location.

Rivaroxaban

Johnson Francis — Fri, 17 Feb 2012 13:25:03 +0000

Rivaroxaban is direct, specific, competitive factor Xa inhibitor and it has a half life of five to thirteen hours. One third of the drug is cleared directly by the kidneys while two third is metabolized by the cytochrome P 450 enzymes. Rivaroxaban is administered once daily by oral route. There is no need for therapeutic monitoring like warfarin. Rivaroxaban was compared with warfarin in a double blind randomized control trial known as ROCKET-AF. Warfarin was maintained at a target INR (internationally normalized ratio of prothrombin time) between 2 to 3. Around fourteen thousand patients with non valvar atrial fibrillation and additional risk factors (two or three of the following: congestive heart failure, hypertension, age seventy five or above, diabetes mellitus) or with a history of stroke, TIA (transient ischemic attack) or systemic embolism were included in the study. The dosage of rivaroxaban was 20 milligrams daily (15 milligrams daily for those with creatinine clearance between 30 and 49 milli liters per minute). Patients were monitored monthly and standard care guidelines were followed. The primary end point was stroke or non central nervous system systemic embolism. The cumulative event rate was 1.71 percent with rivaroxaban and 2.16 percent with warfarin with P value or non inferiority of <0.001. The investigators found that rivaroxaban is not inferior to warfarin for prevention of stroke and non central nervous system systemic embolism. Rivaroxaban was superior to warfarin while patients were taking the study drug and the bleeding rates as well as other adverse event rates were similar. There was less intracranial hemorrhage and fatal bleeding with rivaroxaban. Finally they concluded that rivaroxaban is an alternative to warfarin for those with moderate or high risk for stroke in atrial fibrillation.

Apixaban

Johnson Francis — Mon, 06 Feb 2012 17:36:48 +0000

Apixaban is a direct factor Xa inhibitor. It has an oral bioavailability of about fifty percent. Peak plasma Levels are achieved in three hours and the half-life is about 12 hours. Apixaban is metabolized in liver via CYP3A4 and other CYP independent mechanisms. It is eliminated via multiple pathways and no laboratory monitoring required during therapeutic administration. The utility of apixaban in preventing stroke in non valvar atrial fibrillation has been evaluated in two trial. ARISTOTLE compared apixaban with warfarin and found that it reduces stroke without an increase in bleeds. AVERROES trial compared apixaban with aspirin in those in whom vitamin K antagonists were not usable as in those who were unwilling or unable to monitor INR (internationally normalized ratio of prothromibin time). In this study also, apixaban reduced stroke without increasing major bleeds.

Tecarfarin

Johnson Francis — Mon, 06 Feb 2012 17:35:45 +0000

Tecarfarin is a vitamin K analogue which acts by inhibiting vitamin K epoxide reductase. Tecarfarin is highly bound to plasma proteins and has a half life of nearly five days (119 hours). It is not metabolized by cytochrome P450 enzyme system. Instead, the metabolism is by hepatic microsomal carboxylesterases. Hence it has less potential for drug interactions, unlike warfarin. Another advantage is the availability of INR (internationally normalized ratio of prothrombin time) monitoring with a well established therapeutic range. Moreover, unlike other newer antithrombotic agents which do not have antidotes, the action of tecarfarin is reversible by the administration of vitamin K. EmbraceAC compared tecarfarin with warfarin in a randomized double blind trial of those requiring long term anticoagulation: with atrial fibrillation, prosthetic heart valve, venous thromboembolism or a history of myocardial infarction or cardiomyopathy. The primary outcome was control of INR in the form of time in therapeutic range. Six hundred odd patients were enrolled and treated for six months. The time in therapeutic INR range was 74 percent for tecarfarin and 73.2 percent for warfarin (P = 0.506). Authors attribute the surprisingly high time in therapeutic range for warfarin in this trial to be due to the skill of physicians at the dose control center.

DNB Cardiology accredited hospitals in Kerala, India

Johnson Francis — Sun, 05 Feb 2012 13:49:49 +0000

DNB Cardiology accredited hospitals in Kerala, India, as per the query result from www.natboard.edu.in, the official website of National Board of Examinations, New Delhi, India (accessed on 18th February, 2012):

Sudhamayi Hospitals & Clinics, Kollam, Kerala (old name Amrita Instt. of Medical Sciences), Kerala: 4 seats

Kerala Institute of Medical Sciences, Kumarapuram, Poondhi Road, Anamukham, TRIVANDRUM, Kerala: 1 seat

Malabar Institute of Medical Sciences Ltd., Mini Bye Pass, Govindapuram, KOZHIKODE-16 Kerala: 1 seat

Medical Trust Hospital, M. G. Road, KOCHI-16, Kerala: 1 seat

Pushpagiri Heart Institute, Tiruvalla, Kerala: 1 seat

Lisie Medical Institution, KOCHI-18, Kerala: 2 seats

Baby Memorial Hospital, CALICUT, Kerala: 2 seats

DNB Cardiology program at Baby Memorial Hospital, Calicut, Kerala, India

Johnson Francis — Sun, 05 Feb 2012 09:50:56 +0000

Baby Memorial Hospital, Calicut, Kerala, India, has been accredited for DNB Cardiology program by the National Board of Examinations, New Delhi, India for 2 seats. The cardiology department at Baby Memorial Hospital has seven cardiologists including four former professors of cardiology from Calicut Medical College. The department has an active interventional cardiology program. The department profile can be accessed at: http://babymhospital.org/index.php?option=com_content&view=article&id=83&Itemid=171

Faster degeneration of bioprosthetic valves in diabetics

Johnson Francis — Wed, 01 Feb 2012 01:46:23 +0000

A study involving twelve centers between 1988 and 2009 by Lorusso R et al [Type 2 Diabetes Mellitus Is Associated With Faster Degeneration of Bioprosthetic Valve
Results From a Propensity Score–Matched Italian Multicenter Study. Circulation.
2012; 125: 604-614] has found that bioprosthetic valves degenerate faster in patients with type 2 diabetes mellitus. There were about six thousand and two hundred patients the database analyzed, of which over one thousand and seven hundred were having type 2 diabetes mellitus. Propensity score matching algorithm was used to match 1113 patients with type 2 diabetes mellitus with the same number of those without diabetes mellitus. The one month mortality was 7.8 percent in diabetics while it was only 2.9 percent in the non diabetics. Seven year freedom from valve deterioration was 95.4 percent in the non diabetics while its was only 73.2 percent in diabetics. Diabetes mellitus was found to be the strongest predictor for structural valve degeneration with a hazard ratio of 2.39. This association was found even after adjusting for other important risk factors.

Newer antithrombotics in atrial fibrillation

Johnson Francis — Sat, 28 Jan 2012 14:16:36 +0000

Why do we need newer antithrombotics in atrial fibrillation? It is well known that long term anticoagulation reduces the incidence of stroke in non valvar atrial fibrillation. Vitamin K antagonists like warfarin are highly effective for long term anticoagulation and stroke prevention. But they have numerous limitations including erratic control and drug interactions which are challenging for physicians and patients. Hence the search for newer antithrombotics for stroke prevention in atrial fibrillation.

Newer antithrombotics for atrial fibrillation include the direct thrombin inhibitor dabigatran, direct factor Xa inhibitors like rivaroxaban, apixaban and edoxaban as well as the vitamin K analogue tecarfarin. Otamixaban is a potential intravenous alternative for the acute care setting. In general, direct thrombin and factor Xa inhibitors are small, synthetic molecules with Predictable pharmacokinetics and pharmacodynamic effect, having few drug interactions and do not require routine therapeutic drug monitoring.

Polymer free amphilimus stent better than paclitaxel eluting stent?

Johnson Francis — Sat, 28 Jan 2012 01:35:55 +0000

Carrid D and colleagues [A Multicenter Randomized Trial Comparing Amphilimus- With Paclitaxel-Eluting Stents in De Novo Native Coronary Artery Lesions. J Am Coll Cardiol, doi:10.1016/j.jacc.2011.12.009 (Published online 25 January 2012)] from Europe have compared polymer free amphilimus eluting stents with permanent polymer coated paclitaxel eluting stents in percutaneous coronary interventions of de novo lesions. The primary end point was angiographic late lumen loss at six months. One fifth of the patients had also undergone intravascular ultrasound (IVUS) evaluation. The duration of clinical follow up was five years. Among the three hundred and twenty odd patients studied, the clinical end points of cardiac death, myocardial infarction, target vessel revascularization (TLR) and stent thrombosis was similar between the two groups at one year. In stent late lumen loss was lower with amphilimus stent (0.14 ± 0.36 mm vs. 0.34 ± 0.40 mm, with p for both noninferiority and superiority <0.0001). The authors claim that the polymer free amphilimus stent has a significantly lower in stent late lumen loss and a trend towards better one year clinical safety and efficacy in the treatment of de novo coronary lesions. The stent technology is based on polymer free abluminal reservoir elution which avoids the exposure of the vessel wall to polymers present in the luminal side of conventional drug eluting stents which are potentially proinflammatory and may impair the healing of the vessel. The authors also claim that this feature may potentially reduce the need for prolonged dual anti platelet therapy with its attendant complications. We need more large scale randomized head to head comparisons of the various new generation coronary stents to get the final answer on which is the better of the lot.