Transvalvular in vivo gradients of the new generation bileaflet heart valve prosthesis St. Jude Medical Regent in aortic position.

BACKGROUND: By changing the design of the St. Jude Medical Regent prosthesis in shifting both sewing cuff and retaining ring into a completely supra-annular position, the Regent valve has a greater geometric orifice for a given outer diameter. Accordingly, in vitro studies have shown increased effective orifice areas (EOAs) and lower transvalvular gradients. The aim of our study was to determine in vivo transvalvular gradients and EOAs in patients after aortic valve replacement (AVR). METHODS: We investigated 75 patients at 12 to 21 months follow-up after AVR using transthoracic echocardiography. We determined left ventricular systolic and diastolic function, EOA, and transvalvular peak gradient parameters at rest. Outcomes were assessed using the NYHA classification and functional status. RESULTS: No patient experienced cardiac failure. The majority reported good functional status and good quality of life. Five (6.7 %) late deaths were observed within the surveillance period. At follow-up, 92 % of the patients had improved by at least one NYHA class. Transvalvular peak gradients at rest for patients with Regent valves were 25.4 +/- 7.7 mmHg, 19.2 +/- 4.6 mmHg, 15.6 +/- 5.8 mmHg, 14.6 +/- 5.5 mmHg, and 8.5 +/- 2.5 mmHg; EOAs were 1.38 +/- 0.32 cm2, 1.62 +/- 0.49 cm2, 2.24 +/- 0.83 cm2, 2.63 +/- 0.70 cm2, and 3.28 +/- 0.34 cm2 for valve sizes 19 mm, 21 mm, 23 mm, 25 mm, and 27 mm, respectively. CONCLUSIONS: The SJM Regent valve shows excellent in vivo hemodynamics as confirmed by echocardiography. Clinically, 92 % of the patients improved by at least one NYHA class.

[Acute aortic syndrome. A thoracic emergency--unfortunately with a large selection of symptoms]. / Das akute Aortensyndrom. Ein thorakaler Notfall--leider mit grosser Symptom-Bandbreite!

Acute aortic arch syndrome is a medical emergency associated with a high mortality rate. In view of the great variation in symptomatology, this condition can readily be overlooked. A carefully obtained history (pain!), a thorough physical examination (differences in pulse and blood pressure) may be suspicious for acute aortic arch syndrome, which today can be reliably and rapidly diagnosed by noninvasive imaging (CT, TEE). Confirmation of the suspected diagnosis must be followed by further intensive medical surveillance (Stanford B) or, in the event of involvement of the ascending aorta or aortic arch (Stanford A), referral without delay to a cardiosurgical center. Apart from a further shortening of the time lapse between diagnosis establishment and emergency surgery, new therapeutic (e.g. stenting) and surgical procedures may improve the prognosis of the syndrome. Maybe new diagnostic tools (monoclonal antibodies against aortic myosin and radio-immunoscintigraphy) will help to recognize the aortic syndrome more rapidly.

Prospective crossover comparison of carvedilol and metoprolol in patients with chronic heart failure.

OBJECTIVES: This study investigates the effects of a change of beta-adrenergic blocking agent treatment from metoprolol to carvedilol and vice versa in patients with heart failure (HF). BACKGROUND: Beta-blockers improve ventricular function and prolong survival in patients with HF. It has recently been suggested that carvedilol has more pronounced effects on left ventricular ejection fraction (LVEF) compared with metoprolol. It is uncertain whether a change from one beta-blocker to the other is safe and leads to any change of left ventricular function. METHODS: Forty-four patients with HF due to ischemic (n = 17) or idiopathic cardiomyopathy (n = 27) that had responded well to long-term treatment with either metoprolol (n = 20) or carvedilol (n = 24) were switched to an equivalent dose of the respective other beta-blocker. Before and six months after crossover of treatment, echocardiography, radionuclide ventriculography and dobutamine stress echocardiography were performed. RESULTS: Six months after crossover of beta-blocker treatment, LVEF had further improved with both carvedilol and metoprolol (carvedilol: 32 +/- 3% to 36 +/- 4%; metoprolol: 27 +/- 4% to 30 +/- 5%; both p < 0.05 vs. baseline), without interindividual differences. There were no changes in either New York Heart Association functional class or any other hemodynamic parameters at rest. Dobutamine stress echocardiography revealed a more pronounced increase of heart rate after dobutamine infusion in metoprolol- compared with carvedilol-treated patients. After dobutamine infusion, LVEF increased in the carvedilol- but not in the metoprolol-treated group. CONCLUSIONS: When switching treatment from one beta-blocker to the other, improvement of LVEF in patients with HF is maintained. Despite similar long-term effects on hemodynamics at rest, beta-adrenergic responsiveness is different in both treatments.

[Angiographically unexplained myocardial ischemia in high grade coronary stenosis with main stem involvement in intravascular ultrasound]. / Angiographisch ungeklärte Myokardischämie bei hochgradiger Koronarstenose mit Hauptstammbeteiligung im intravaskulären Ultraschall.

HISTORY AND ADMISSION FINDINGS: For seven weeks a 57-year-old man had been complaining of recurrent non-radiating retrosternal pain and pressure on slightest exertion. Admission physical examination was unremarkable except for evidence of peripheral vascular disease. Cardiovascular risk factors were hypertension, hyperlipoproteinaemia and obesity. INVESTIGATIONS: The resting ECG was unremarkable. Objective signs of myocardial ischaemia were produced in the exercise ECG (angina at 100 Watt, negative T waves in V2 to V6 and borderline S-T depression in V4). Myocardial scintigraphy showed reversible reduced perfusion of the anterior wall near the apex and also of the apex and septum. Left ventricular (LV) angiography demonstrated a normally contracting LV, while selective coronary angiogram revealed a 20% reduction in caliber of the proximal branch of the anterior interventricular branch (AIVB), with otherwise normal coronary arteries. Subsequent intravascular ultrasound (IVUS) showed a circular echo-poor 80% stenosis at the origin of the AIVB with extension to the main stem. TREATMENT AND COURSE: A bypass from the internal mammary artery to the AIVB and an aortocoronary venous bypass to the intermediate branch were performed. The patient was free of symptoms postoperatively. CONCLUSION: If cases where there is a discrepancy between clinical and coronary angiographic findings--the latter being unclear or inconsistent, especially in the area of the left main stem, bifurcations or vessel origin--IVUS may contribute decisively to demonstrating coronary anatomy or pathology, and to indicating the type of revascularizing measures.

Identification of hemodynamically significant restenosis after percutaneous transluminal coronary angioplasty in acute myocardial infarction by transesophageal dobutamine stress echocardiography and comparison with myocardial single photon emission computed tomography.

BACKGROUND: Beside thrombolysis, percutaneous transluminal coronary angioplasty (PTCA) has become a well-established treatment for acute myocardial infarction. However, restenosis occurs in approximately 15%-40% of patients. Despite a frequently occurring infarct-related regional systolic dysfunction at rest, the identification of hemodynamically relevant restenosis seems important in terms of risk stratification, adequate treatment, and possible improvement of prognosis in these patients. This study was designed to assess the role of transesophageal dobutamine stress echocardiography and myocardial scintigraphy for identification of hemodynamically significant restenosis after PTCA for acute myocardial infarction. METHODS: Multiplane transesophageal stress echocardiography (dobutamine 5, 10, 20, 30, and 40 micrograms/kg per min) studies and myocardial single photon emission computed tomography (SPECT) studies were performed in 40 patients, all of whom underwent PTCA in the setting of acute myocardial infarction > or = 4 months prior to the test. Repeated coronary angiography was performed in all study patients who showed stress-induced perfusion defects or wall-motion abnormalities, or both. RESULTS: Significant restenosis (> or = 50%) was angiographically found in 15 (37.5%) of 40 patients. Of these 15 patients, transesophageal dobutamine stress echocardiography identified restenosis in 12 (80%) and myocardial SPECT in 14 (93%), yielding diagnostic agreement in 70% of patients. Echocardiographic detection of restenosis was based mainly on a biphasic response to increasing doses of dobutamine. Sensitivity and specificity for identification of hemodynamically relevant restenosis in individual patients was 80% and 92%, respectively for dobutamine stress echocardiography versus 93% and 68% for myocardial SPECT. CONCLUSIONS: Both transesophageal dobutamine stress echocardiography and myocardial SPECT were highly sensitive in identifying significant restenosis after PTCA for acute myocardial infarction. Therefore, either test, as a single diagnostic tool or especially if performed together, are clinically valuable alternatives to coronary angiography for the detection of restenosis after PTCA for acute myocardial infarction.

Reduction of fat embolic risks in total hip arthroplasty using cannulated awls and rasps for the preparation of the femoral canal.

Fat embolic phenomena during cemented and non-cemented total hip arthroplasty occur even during the preparation of the femoral canal. This should be avoided in order to reduce the rate of fat embolic syndrome. In the present prospective study we demonstrate the benefit of cannulated awls and rasps in the reduction of fat embolic phenomena by means of transoesophageal echocardiography and extended cardiopulmonary monitoring. Two groups of 5 patients each with identical surgical procedures were treated either with cannulated (group 1) or with closed (group 2) awls and rasps. In group 1 no macroemboli but three embolic showers grades 1 and 2 were seen. In contrast to these findings, three macroemboli and four embolic showers grades 1 and 3 were demonstrated in group 2. We recommend cannulated awls and rasps for the preparation of the femoral canal in cemented and non-cemented total hip arthroplasty. They are a simple and inexpensive aid to avoid fat embolic syndrome.

Comparison of dobutamine transesophageal echocardiography and dobutamine magnetic resonance imaging for detection of residual myocardial viability.

A dobutamine-induced contraction reserve in akinetic but viable myocardium, observed by echocardiography or magnetic resonance imaging (MRI), is a reliable indicator of myocardial viability. However, the comparative diagnostic accuracy of these 2 techniques is unknown. Therefore, 43 patients with myocardial infarction (infarct age > or = 4 months) and regional akinesia underwent dobutamine transesophageal echocardiography (TEE) and dobutamine MRI (10 microg dobutamine/ min/kg). Both imaging techniques were compared with the reference standard 18F-fluorodeoxyglucose positron emission tomography (FDG PET). An infarct region was considered viable if a dobutamine contraction reserve could be assessed visually by TEE or quantitatively by MRI in > or = 50% of segments graded "a" or dyskinetic at rest. Infarct regions were graded viable by PET if FDG uptake was > or = 50% of the maximal FDG uptake in a region with normal wall motion by left ventriculography. A dobutamine contraction reserve was found in 21 of 43 patients (49%) by TEE and MRI. A viable infarct region by FDG PET was diagnosed in 26 of 43 patients (60%). FDG uptake and dobutamine TEE were concordant in 36 of 43 patients (84%) and dobutamine MRI and FDG PET were concordant in 38 of 43 patients (88%). Sensitivity and specificity of dobutamine TEE and dobutamine MRI for FDG PET-defined myocardial viability were 77% versus 81% and 94% versus 100%, respectively. Both imaging techniques yielded similar results for the detection of myocardial viability as defined by FDG uptake, with a slightly higher sensitivity and specificity for the quantitatively evaluated dobutamine contraction reserve by MRI.