Biomedical subjects

Henning Kelbaek

Publications and source records attributed to Henning Kelbaek.

26 records · Page 2Linked to original sources

PubMed2002

[Is use of surgical caps and masks obsolete during percutaneous heart catheterization?].

INTRODUCTION: Despite the lack of scientific evidence, surgical caps and masks are worn routinely by many physicians and nurses in the catheterisation laboratories to avoid local and generalised infections. When we changed our practice, we performed a randomised study to assure the quality of our routine. MATERIAL AND METHODS: All patients undergoing left- or right-sided cardiac catheterisation were randomly allocated to our five laboratories. About two months after the procedure, the patients were sent a questionnaire concerning signs and symptoms of possible inflammation or infection after the procedure. RESULTS: Of 1,034 patients, 855 (82.7%) responded to the questionnaire. Although 25 patients in the caps and mask group vs 19 patients in the other group (6.1% vs 4.3%, ns) had complaints from the procedural access site in the groin, none of these could be ascribed to definite infection. DISCUSSION: The use of caps and masks during percutaneous cardiac catheterisation procedures is based on the concept that the infection rate of patients is reduced. The size of the catheter used, procedure time, and the use of caps and masks by both the surgeon and the assisting staff are discussed. CONCLUSION: The routine use of caps and masks does not seem to have that much beneficial impact on the occurrence of procedure-related inflammations or infections in the cardiac catheterisation laboratory.

Angioplasty, Balloon, Coronary↗

PubMed2002

Prolonged ischemic heart disease and coronary artery bypass - relation to contractile reserve.

OBJECTIVE: A major effect of coronary artery bypass grafting (CABG) in patients with ischemic heart disease and impaired left ventricular (LV) contractile function is believed to be an improvement in LV function due to recovery of dysfunctional, but viable myocardium. However, recent studies have indicated a time limit for such a recovery. We therefore investigated the extent of viable myocardium in patients with impaired LV function due to ischemic heart disease after a prolonged strategy of medical treatment and its relation to changes in clinical variables after CABG. METHODS: Forty-five consecutive patients with a mean duration of ischemic heart symptoms of 9 years and LV ejection fraction (EF) <45% referred for CABG were included and LV extent of viable myocardium was measured preoperatively by glucose metabolism--blood flow positron emission tomography imaging and dobutamine stress echocardiography. Symptoms, exercise-capacity and LV function were evaluated before and 7 months after surgery in event-free survivors. RESULTS: LV extent of myocardial viability was <30% in most patients. In event-free survivors, LVEF decreased from 31+/-7 to 26+/-8% 7 months after CABG. The decrease in LVEF was correlated to the LV extent of myocardial metabolism--blood flow reverse mismatch. Most of the patients experienced an improvement in their angina pectoris, heart failure symptoms and exercise capacity after CABG; the overall 3-year survival was 77%. CONCLUSIONS: Patients with chronic ischemic heart disease and impairment of LV function, in whom an initial long-standing conservative treatment has been practiced, benefit from CABG, despite a lack of LV functional reserve.

Coronary Artery Bypass↗

PubMed2002

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation.

BACKGROUND: Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS: In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS: One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION: Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.

Coronary Circulation↗

PubMed2002

Between observer variation is not eliminated by standardised analysis of dobutamine-atropine stress echocardiography.

AIMS: The conventional analysis of dobutamine-atropine stress echocardiography (DASE) is poorly defined and subject to considerable variation. The aim of this study was to investigate the reproducibility of strictly standardised qualitative analysis in DASE. METHODS AND RESULTS: Strict criteria for standardised DASE interpretation were defined through logistic regression analysis on categorical parameters obtained from 20 patients with coronary artery disease (CAD) and 20 healthy controls subjected to DASE. Three expert echocardiographers analysed DASE recordings from 100 consecutive patients referred for coronary angiography. Specificity for CAD and for predicting significant stenosis of a major coronary artery was 94% (95% CI: 83-100%) and 79% (95% CI: 63-96%), whereas sensitivity was 49% in both cases (95% CI: 38-60% and 37-61%). Within and between observer reproducibility was moderate to fair (kappa = 0.56 and 0.38; 95% CI: 0.40-0.72 and 0.24-0.52). In patients without prior myocardial infarction and in echogenic patients within observer reproducibility was good (kappa = 0.72 and 0.74; 95% CI: 0.52-0.92 and 0.56-0.92). CONCLUSIONS: Observer variation was not eliminated in standardised qualitative DASE interpretation based on criteria that predicted the presence of CAD with a high specificity and reproducibility was good only in certain subgroups of patients.

Adult↗

PubMed2002

A maximum entropy method to compute the 13NH3 pulmonary transit time from right to left ventricle in cardiac PET studies.

The distribution function of pulmonary transit times (fPTTs) contains information on the transit time of blood through the lungs and the dispersion in transit times. Most of the previous studies have used specific functional forms with adjustable parameters to characterize the fPTT. It is the purpose here to investigate the possibility of estimating the fPTT in a model-free way. The method employs the maximum entropy principle and is used, in particular, on cardiac positron emission tomographic (PET) studies but is believed to be more generally applicable. Using this principle in a test case, we were able to accurately identify a two-peaked transfer function, which may theoretically be seen in patients with pulmonary disease confined to one lung. Transit time values for [13N]-ammonia were produced by applying the algorithm to PET studies from normal volunteers.

Algorithms↗

PubMed2002

Yield of 5,536 diagnostic coronary arteriographies: results from a data registry.

The number of coronary arteriographies (CAG) has increased tremendously all over the industrialised world over the past years. Even though the potential benefit is high in patients with angina pectoris, for example, with expected life prolongation in case of three-vessel disease or left main stenosis with subsequent coronary artery bypass grafting (CABG), the indication for treatment is not as dramatic in all patients and at the same time CAG is a procedure with at least, some risk, and costs are not negligible. It is therefore pertinent, and hence also the purpose of the present analysis, to make observations on indications, clinical and angiographic findings and their combinations which could be helpful in clinical practice/decision-making. Furthermore, the purpose was to analyse the consequences of CAG with respect to revascularisations such as percutaneous transluminal coronary angioplasty (PTCA) or CABG.

Adolescent↗

PubMedDate not supplied

Absolute quantitation of left ventricular wall and cavity parameters using ECG-gated PET.

BACKGROUND: Electrocardiography (ECG)-gated scintigraphy demonstrates promising results for the simultaneous assessment of myocardial glucose metabolism and contractile function. In this study a method was evaluated for absolute quantitation of left ventricular wall and cavity parameters with the use of fluorine 18 fluorodeoxyglucose (FDG) ECG-gated positron emission tomography (PET). METHODS AND RESULTS: A previously developed 2-dimensional mathematical model was implemented for computer-automated identification of endocardial and pericardial borders. The accuracy and precision were tested in a heart phantom and in healthy subjects. Twelve healthy men aged 64 +/- 8 years were studied by use of cine magnetic resonance imaging (MRI) and ECG-gated FDG-PET during euglycemic glucose-insulin clamp. At increasing image noise levels, the estimated cavity volume of the heart phantom was within 2 mL of the actual volume, and no significant difference was found between actual and estimated wall thicknesses. Endocardial wall motion as assessed by ECG-gated PET in the healthy subjects was systematically underestimated compared with MRI. This underestimation correlated linearly with endocardial excursion during PET end diastole as measured by MRI. Myocardial end-diastolic wall thickness was systematically overestimated by PET, whereas end-systolic thickness deviated less than 1 mm from MRI. Cavity volumes measured by PET correlated linearly with MRI, with a tendency toward an underestimation of end-diastolic cavity volumes by PET. CONCLUSIONS: Absolute measures of cardiac structure and function may be obtained with a reasonable degree of accuracy by use of ECG-gated PET imaging. However, a high ECG-gating frequency appears to be required to obtain measurements comparable to what may be achieved by MRI.

Aged↗

PubMedDate not supplied

Simultaneous cardiac output and regional myocardial perfusion determination with PET and nitrogen 13 ammonia.

BACKGROUND: The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia. METHODS AND RESULTS: In 7 patients undergoing right-sided cardiac catheterization for evaluation of heart failure and 6 patients who had undergone heart transplantation, a thermodilution catheter for continuous measurement of cardiac output was inserted. An N-13 ammonia scan of the heart was subsequently performed, and with use of factor analysis, the time-activity curve from the right ventricle was derived from the dynamic image sequence. The PET-derived cardiac output was subsequently obtained according to the Stewart-Hamilton principle as the amount of injected tracer divided by the area under the time-activity curve. PET-acquired cardiac output measurements correlated closely with the invasively determined values for a wide range of cardiac output values (P < .0001). The mean difference was 0.12 L/min, with an SD of 0.74 L/min. The interobserver variation was low, with a mean difference of 0.06 L/min and an SD of 0.46 L/min. CONCLUSIONS: Cardiac output determination with N-13 ammonia and PET appears to be both accurate and precise and can be performed simultaneously with measurement of myocardial perfusion.

Adult↗