Manufacturer-provided effective orifice area index charts and the prevention of prosthesis-patient mismatch.

Prosthesis-patient mismatch (PPM) occurs when an implanted prosthesis is too small relative to the patient's body surface area (BSA). However, mismatch can often be prevented by indexing the expected effective orifice area (EOA) of a prosthesis to the patient's BSA and then selecting the largest implantable prosthesis to avoid mismatch. Previously, prosthesis manufacturers have attempted to simplify this process by providing charts that include the expected EOA for their prosthesis, already indexed into an array of BSA values. One caveat with these charts is that the expected EOA data must truly be reliable, or the charts will misguide the implanting surgeon. Manufacturer-provided charts could be improved by standardizing the EOA data, with one potential source being the hemodynamic data submitted to the United States Food and Drug Administration. This review discusses PPM, manufacturer-provided EOA charts, and the regulation of EOA data.

Mitral valve area by the pressure half-time method does not correlate with mean gradient in mitral valve repair patients.

AIMS: Pressure half-time is an inaccurate measure of mitral valve area in many clinical situations. The utility of the pressure half-time method to calculate mitral valve area after mitral valve repair is not well defined. METHODS AND RESULTS: Forty-two patients with a repaired mitral valve were identified. Mitral valve area was calculated by both the pressure half-time method and the continuity equation. The two mitral valve areas were then directly compared and also correlated with mean gradient. The two mitral valve areas were significantly different from one another with a mean of 1.81 ± 0.53 cm(2) by continuity equation and 2.65 ± 0.69 cm(2) by pressure half-time. The continuity equation correlated well with mean gradient (ρ = -0.63), whereas the correlation for pressure half-time was weak (r = -0.08). CONCLUSION: A non-linear, inverse correlation was found between mitral valve area by the continuity equation and mean gradient. No correlation was found between the pressure half-time method for mitral valve area and mean gradient. The continuity equation likely provides a better estimate of mitral valve area in repaired mitral valves.

Continuing warfarin therapy is superior to interrupting warfarin with or without bridging anticoagulation therapy in patients undergoing pacemaker and defibrillator implantation.

BACKGROUND: Current guidelines recommend stopping oral anticoagulation and starting bridging anticoagulation with intravenous heparin or subcutaneous enoxaparin when implanting a pacemaker or defibrillator in patients at moderate or high risk for thromboembolic events. A limited body of literature suggests that device surgery without cessation of oral anticoagulation may be feasible. OBJECTIVE: The purpose of this study was to evaluate the safety of device surgery in orally anticoagulated patients without interrupting warfarin therapy. METHODS: We performed a retrospective study of 459 consecutive patients on chronic warfarin therapy who underwent device surgery from April 2004 to September 2008. Warfarin was continued in 222 patients during the perioperative period. Warfarin was temporarily held and bridging therapy administered in 123 patients. Warfarin was temporarily held without bridging therapy in 114 patients. RESULTS: There were no significant differences with regard to age, sex, or risk factors for thromboembolism in the three groups. Patients who continued taking warfarin had a lower incidence of pocket hematoma (P = .004) and a shorter hospital stay (P <.0001) than did patients in the bridging group. Holding warfarin without bridging is associated with a higher incidence of transient ischemic attacks (P = .01). CONCLUSION: Temporarily interrupting anticoagulation is associated with increased thromboembolic events, whereas cessation of warfarin with bridging anticoagulation is associated with a higher rate of pocket hematoma and a longer hospital stay. Continuing warfarin with a therapeutic international normalized ratio appears to be a safe and cost-effective approach when implanting a pacemaker or defibrillator in patients with moderate to high thromboembolic risk.

How reliable is an effective orifice area indexed chart?

BACKGROUND AND AIM OF THE STUDY: Patient-prosthesis mismatch (PPM) occurs when a valvular prosthesis is too small relative to the patient's body surface area (BSA). The presence of PPM results in increased transprosthetic gradients and may portend a worse prognosis. It has been shown that reliable effective orifice area (EOA) data can be used to accurately predict PPM, thus preventing its occurrence. The study aim was to assess the predictive abilities of an effective orifice area indexed (EOAI) chart--the Perimount Magna EOAI chart--in the prevention of PPM. METHODS: A retrospective comparison of projected versus calculated EOA values and the predicted versus actual incidence of PPM was conducted. Forty patients with a Perimount Magna aortic bioprosthesis implanted between 1st January 2006 and 31st March 2009, were identified. The sensitivity, specificity, positive-predictive value (PPV) and negative predictive value (NPV) were each calculated using the Perimount Magna EOAI chart, to assess how well it could predict the incidence of postoperative PPM. RESULTS: The Perimount Magna EOAI chart had a sensitivity of 35% for predicting postoperative PPM, and an NPV of 53%. The projected EOA-values were almost invariably larger than those actually measured; this resulted in a higher proportion of patients than in whom PPM was predicted preoperatively. This EOAI chart proved to be very specific, with specificity of 100% and a PPV of 100%. CONCLUSION: The Perimount Magna EOAI chart, based on mean EOA data from a small echocardiographic cohort, represents a poor method of predicting and preventing PPM. Rather, EOAI charts should be based on reliable EOA data that reproducibly predict the expected EOA for that prosthesis.

Acute coronary thrombosis in a patient with septic shock without any evidence of disseminated intravascular coagulation.

The case report describes an interesting and unusual finding of acute coronary artery thrombosis in a patient presenting with septic shock without any clinical and laboratory evidence of disseminated intravascular coagulation (DIC). The patient presented with leucocytosis and refractory hypotension requiring pressor support and found to have anterior and inferior ST-elevation in 12-lead electrocardiogram. Coronary angiogram revealed acute thrombotic occlusions in the proximal right coronary artery and the proximal left anterior descending coronary artery. There was no occlusive atherosclerotic coronary artery disease. The patient underwent mechanical thrombectomy. Haemodynamic parameters obtained from right heart catheterisation confirmed sepsis as the aetiology of hypotension. The patient was treated successfully with broad spectrum antibiotics, pressors and intravenous fluid.Acute myocardial infarctions as a complication secondary to disseminated intravascular coagulation in patients with sepsis and septic shock have been described in the literature. To our knowledge, this is the first reported case of acute coronary artery thrombosis in patient with septic shock without DIC and without any underlying occlusive coronary artery disease.

Sudden cardiac arrest in apical hypertrophic cardiomyopathy.

We present two cases of cardiac arrest, presumably attributable to apical hypertrophic cardiomyopathy(HCM). The first case was a 37-year-old Asian man known to have an apical HCM and was successfully resuscitated from an "out of hospital" ventricular fibrillation arrest. He underwent an electrophysiological study that was unable to induce tachyarrhythmias, which may not be surprising. He did receive an automated internal cardioverter defibrillator (AICD) in compliance with his class I indication for an implantable defibrillator. The second patient was an 86-year-old Caucasian woman with a cardiac history significant for apical HCM, coronary artery disease, diastolic heart failure, and monomorphic ventricular tachycardia. She underwent electrophysiological testing for frequent dizziness and monomorphic ventricular tachycardia of a right ventricular origin was induced. She received an AICD for sudden cardiac death prevention. Though lethal ventricular arrhythmias have been reported in patients with apical HCM, the prevailing consensus is that the prognosis of apical HCM is benign. Whether these accounts are truly exceptional occurrences for this rare and conventionally regarded benign condition or whether they represent an under-appreciated risk for sudden cardiac arrest is an intriguing question.

Myocardial ischemia and congestive heart failure from a left main to coronary sinus fistula.

A coronary artery fistula (CAF) is a rare congenital anomaly first reported by Krause in 1865. It is defined as a direct communication between the coronary artery and any surrounding cardiac chamber or vascular structure, which bypasses the myocardial capillary bed. The incidence of small CAFs in an adult population, undergoing cardiac catheterization at the Cleveland Clinic, was 0.13%. In the same series, the incidence of large or multiple fistulas was less than that of small fistulas and was present in 0.05% of all patients screened. The natural history of CAF in adults remains undefined, as does the best approach to managing these patients with recommendations for early closure as well as conservative management found in the medical literature. We present a patient initially diagnosed with a clinically silent CAF who presents 10 years later with symptoms and many of the classic findings of a CAF. An alternative model for the management of CAF in adults is discussed.