Biomedical subjects

Guy J Friedrich

Publications and source records attributed to Guy J Friedrich.

7 recordsLinked to original sources

PubMed2006

Multislice computed tomography for detection of patients with aortic valve stenosis and quantification of severity.

OBJECTIVES: The purpose of this study was to evaluate whether multislice computed tomography (MSCT) provides a reliable, noninvasive imaging modality for identification of patients with degenerative aortic valve stenosis (AS) by quantifying the aortic valve area (AVA) in comparison to the accepted diagnostic standard transthoracic echocardiography (TTE). BACKGROUND: Management of patients with degenerative AS is based on the severity of disease. The severity of AS in clinical practice is assessed by TTE and classified as mild, moderate, or severe according to the AVA. METHODS: Forty-six patients were examined with contrast-enhanced, electrocardiogram-gated, 16-row MSCT for the evaluation of the diagnostic accuracy. In 30 patients, quantification of the AVA with MSCT was compared to TTE using the continuity equation with Doppler velocity-time integral for calculation of the AVA. RESULTS: Sensitivity of MSCT for the identification of patients with degenerative AS was 100%, and the specificity was 93.7%. Thirty of 46 patients had AS determined by TTE. Quantification of AVA by MSCT (mean AVA = 0.94 cm2) in patients with AS showed a good correlation to TTE (r = 0.89; p < 0.001). Bland-Altman plot illustrated good intermodality agreement between the two methods (limits of agreement, 0.20; 0.29). CONCLUSIONS: Multislice computed tomography may provide an accurate, noninvasive imaging technique for detection of patients with AS and quantification of AVA.

Aged↗

PubMed2006

Reduction of soluble P-selectin by statins is inversely correlated with the progression of coronary artery disease.

BACKGROUND: Cell adhesion molecules (CAM) play an important role in the pathogenesis of atherosclerosis by mediating the binding of leukocytes to the endothelium. Soluble CAM isoforms are known to be elevated in the sera of patients suffering from coronary artery disease (CAD). METHODS: We measured the concentrations of soluble intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, P-selectin, platelet endothelial cell adhesion molecule-1, and highly sensitive C-reactive protein (hs-CRP) in the blood of 47 CAD patients before and 6 months after starting statin therapy and in 16 untreated CAD patients. The progression of CAD was monitored by calculating the coronary calcium score using electron beam computed tomography. RESULTS: Soluble P-selectin (92+/-11 ng/ml vs. 59 +/- 4 ng/ml, p < 0.0001) and hs-CRP (0.92 +/- 0.14 mg/dl vs. 0.42 +/- 0.11 mg/dl, p < 0.001) decreased significantly in the statin-treated group compared to baseline levels. None of the other proteins studied showed significant changes. In contrast to hs-CRP, the reduction of soluble P-selectin concentrations correlated directly with the lowering of total cholesterol (r(2) = 0.236, p < 0.005) and inversely with the progression of CAD (r(2) = 0.393, p < 0.0001). CONCLUSIONS: Our results suggest P-selectin as an additional marker for the beneficial action of statins in patients with CAD.

Analysis of Variance↗

PubMed2006

Evaluation of ascending aortic atherosclerosis with 16-multidetector computed tomography is useful before total endoscopic coronary bypass surgery.

BACKGROUND: The purpose of this study was to investigate the assessment of ascending aortic atherosclerosis with 16-multidetector computed tomography (16-MDCT) angiography prior to total endoscopic coronary artery bypass (TECAB) surgery. METHODS: Forty-five patients were examined with electrocardiogram-gated, 16-MDCT angiography. The presence of atherosclerosis at the ascending aorta was graduated as severe (>50% of circumference) or as mild (<50% of circumference). Ascending aortic plaque composition was evaluated based on CT densities expressed as Hounsfield units (HU). TECABs using the Da Vinci telemanipulator were performed either on the arrested heart (n = 39) with an intra-aortic cardiopulmonary bypass (CPB) perfusion device or on the beating heart (n = 6) in patients with severe atherosclerosis. RESULTS: The presence of mild atherosclerosis at the ascending aorta (11/39) was associated with intra-aortic CPB perfusion device-related difficulties such as intra-aortic balloon migration (BM) or balloon rupture (P = .007) in arrested heart TECABs. The CT density of atherosclerotic plaque in patients with BM was mean 58 HU +/- 51 standard deviation (SD), suggesting noncalcifying plaque. In patients without BM, CT density of plaque was mean 526 HU +/- 306 SD corresponding to calcifying plaque (P < .001). Balloon rupture occurred in 2 patients who had calcifying plaque at the ascending aorta. CONCLUSION: Evaluation of ascending aortic atherosclerosis with 16-MDCT angiography is useful prior to TECAB surgery. Even mild atherosclerosis of the ascending aorta is associated with intraoperative difficulties regarding the remote-access perfusion system that is used for arrested heart TECAB surgery.

Aorta↗

PubMed2006

Diagnostic performance of MDCT for detecting aortic valve regurgitation.

OBJECTIVE: This study evaluates whether ECG-gated 16-MDCT coronary angiography provides a reliable imaging technique for detecting aortic regurgitation (AR). SUBJECTS AND METHODS: We examined 71 patients prospectively with 16-MDCT angiography using retrospective ECG gating during the mid-to-end diastolic phase. A visible central valvular leakage area was considered as a diagnostic criterion for AR. The central valvular leakage area was quantified in patients with positive transthoracic echocardiography (TTE). We compared 16-MDCT to Doppler TTE, the accepted diagnostic standard based on semiquantitative regurgitation jet analysis (grade 0-3+ for mild, moderate, and severe). RESULTS: The overall sensitivity of 16-MDCT for the identification of patients with AR was 81%. The specificity was 91%, the negative predictive value was 70%, and the positive predictive value was 95%. Of the 71 patients, 48 had AR determined by TTE, and 16-MDCT correctly detected AR in 39 of those 48 patients. The sensitivity of 16-MDCT for the detection of patients with moderate and severe AR (grade > or = 1.5+) was 95%, and the specificity was 96% (20 of 21 patients). The sensitivity of 16-MDCT for identification of patients with mild AR (grade < or = 1+) was 70%, and the specificity was 92% (19 of 27 patients). Quantification of the central valvular leakage area was not possible in 50% of cases with AR by TTE because of valve calcifications. CONCLUSION: Sixteen-MDCT coronary angiography provides an accurate, noninvasive imaging technique to detect moderate and severe aortic regurgitation (grade > or = 1.5+). However, severe valve calcifications and mild AR limit its results.

Adult↗

PubMed2006

Aortic valve calcification as quantified with multislice computed tomography predicts short-term clinical outcome in patients with asymptomatic aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Aortic valve calcification may be an independent risk factor for adverse clinical outcome. The study aim was to assess the predictive value of possible risk factors, including the severity of aortic valve calcification as quantified with 16-multislice computed tomography (MSCT) for adverse short-term clinical outcome in patients with asymptomatic, degenerative aortic stenosis (AS). METHODS: Possible risk factors for adverse short-term clinical outcome were prospectively tested in 34 consecutive patients with asymptomatic AS as follows: (i) aortic valve calcium (AVC) score as quantified with MSCT; (ii) echocardiographic parameters--aortic valve area (AVA) calculated with continuity equation, mean and maximal transvalvular pressure gradients, end-diastolic septal wall diameter; and (iii) laboratory tests (brain natriuretic peptide (BNP), C-reactive protein (CRP)). RESULTS: Within 18-24 months of follow up, 11 of 34 patients developed a major adverse clinical outcome. Ten patients suffered from onset of symptoms accompanied by hemodynamic progression, and one patient died from sudden cardiac death. Six of these 10 patients underwent aortic valve replacement, one patient declined surgery, and three patients were not accepted for surgery (one of these died suddenly shortly afterwards). The aortic valve calcium score was the strongest predictor of a major adverse clinical event (p < 0.001) among all parameters assessed (1,928 +/- 789 versus 5,111 +/- 2,409 Agatston units). The plasma level of BNP (p = 0.003), mean transvalvular pressure gradient (p = 0.002) and AVA (p = 0.003) were also risk factors for adverse clinical outcome. CONCLUSION: The AVC score as quantified with MSCT predicted adverse short-term clinical outcome in patients with asymptomatic AS. In patients with severe aortic valve calcification, close follow up examinations are mandatory, and early elective surgery may be considered even in the absence of symptoms. MSCT provides a comprehensive non-invasive imaging approach for risk stratification in patients with asymptomatic AS.

Aortic Valve↗

PubMed2005

Hybrid coronary artery revascularization: logistics and program development.

Planning hybrid coronary artery revascularization--a combination of cardiac surgery with percutaneous procedures--requires, at first sight, a very complex logistical setup. Technical and equipment related details should be defined as early as possible in order to have time for training of all OR personnel involved. The most challenging aspect in OR-located hybrid coronary revascularization remains a very close cooperation of cardiac surgeons and interventional cardiologists. This teamwork does include indication findings and subsequent referral of multivessel coronary artery disease patients to hybrid procedures, as well as high individual flexibility of interventionalists and surgeons. The major prerequisite for this cooperation is a mutual acceptance of different revascularization approaches and the intent to combine their most striking advantages. Intraoperative graft angiography during coronary artery bypass grafting (CABG) procedures is one important step toward simultaneous hybrid coronary revascularization procedures. We describe our experience with on table angiography using a mobile C-arm for intraoperative imaging. This fluoroscopy system can in selected cases be used for simultaneous hybrid procedures.

Adult↗

PubMed2005

High-resolution 16-MDCT evaluation of radial artery for potential use as coronary artery bypass graft: a feasibility study.

OBJECTIVE: The objective of our study was to assess the feasibility of using 16-MDCT angiography for the preoperative assessment of the radial and ulnar arteries and the palmar arches in patients scheduled for radial artery harvesting for coronary artery bypass graft (CABG) surgery. CONCLUSION: Sixteen-MDCT angiography shows promise for the noninvasive preoperative assessment of the radial artery as a CABG donor site.

Aged↗