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Biomedical subjects

H Rickli

Publications and source records attributed to H Rickli.

At least 19 recordsLinked to original sources

N-terminal pro-brain natriuretic peptide used for the prediction of coronary artery stenosis.

BACKGROUND: The level of the inactive N-terminal fragment of pro-brain (B-type) natriuretic peptide (NT-proBNP) is a prognostic marker in patients with acute and chronic coronary artery disease (CAD). It might also be valuable for non-invasive diagnosis of coronary artery disease. MATERIALS AND METHODS: The NT-proBNP was measured in 781 consecutive patients with normal left ventricular function referred for coronary angiography owing to symptoms or signs of CAD. The diagnostic value of NT-proBNP was assessed for predicting CAD at angiography. RESULTS: Elevated NT-proBNP levels were associated with the extent of CAD and with the female sex (P < 0.001). The ability of NT-proBNP to predict significant coronary disease at angiography was assessed separately for men using a cut-off point of 85 pg mL(-1), positive likelihood ratio 2.2 (95% CI, 1.7-3.0), negative likelihood ratio 0.53 (95% CI 0.45-0.63) and area under the receiver-operating-characteristic (ROC) curve 0.72: for women, it was assessed using a cut-off point of 165 pg mL(-1), positive likelihood ratio 2.4 (95% CI, 1.7-3.4), negative likelihood ratio 0.55 (95% CI, 0.44-0.70) and area under ROC curve 0.71. In multiple logistic-regression analysis, NT-proBNP added significant independent predictive power to other clinical variables in models predicting CAD (odds ratio 2.76, 95% CI, 1.76-4.32, P < 0.001). CONCLUSIONS: The NT-proBNP is a marker of non-obstructive CAD and of significant coronary stenosis. In conjunction with other clinical information, measurement of NT-proBNP with the use of sex-specific reference ranges may improve the non-invasive prediction of CAD.

Aged↗

How to set up and apply reference levels in fluoroscopy at a national level.

A nationwide survey was launched to investigate the use of fluoroscopy and establish national reference levels (RL) for dose-intensive procedures. The 2-year investigation covered five radiology and nine cardiology departments in public hospitals and private clinics, and focused on 12 examination types: 6 diagnostic and 6 interventional. A total of 1,000 examinations was registered. Information including the fluoroscopy time (T), the number of frames (N) and the dose-area product (DAP) was provided. The data set was used to establish the distributions of T, N and the DAP and the associated RL values. The examinations were pooled to improve the statistics. A wide variation in dose and image quality in fixed geometry was observed. As an example, the skin dose rate for abdominal examinations varied in the range of 10 to 45 mGy/min for comparable image quality. A wide variability was found for several types of examinations, mainly complex ones. DAP RLs of 210, 125, 80, 240, 440 and 110 Gy cm2 were established for lower limb and iliac angiography, cerebral angiography, coronary angiography, biliary drainage and stenting, cerebral embolization and PTCA, respectively. The RL values established are compared to the data published in the literature.

Diagnostic Imaging↗

Bland-White-Garland syndrome and atrial septal defect - rare association and diagnostic challenge.

We report on a 40-year-old woman referred for evaluation of a cardiac murmur and dyspnea on exertion. The electrocardiogram (ECG) showed incomplete right bundle branch block, and echocardiography revealed a large atrial septal defect (ASD, ostium secundum type) with dilated right-sided heart chambers. At cardiac catheterization, a large left-to-right shunt (78% of the pulmonary blood flow) was found, and surprisingly, the additional diagnosis of anomalous origin of the left coronary artery from pulmonary artery (ALCAPA) was established. After ASD closure and left coronary artery ligation with implantation of a vein graft to the left anterior descending artery, she had an uneventful 18-years follow-up. We discuss the interaction of the two associated conditions, and based on the herein reported unusual combination, we highlight typical features of non-invasive examinations including auscultation, ECG, and echocardiography in adult patients with ALCAPA.

Adult↗

Pregnancy-associated spontaneous coronary artery dissection: impact of medical treatment. Case report and systematic review.

We report on a 22- year-old woman with postpartum dissection of the left anterior descending artery and the intermediate branch. The patient was treated with acetylsalicylic acid (ASA), clopidogrel, and betablocker only. Coronary angiography performed 20 months later revealed complete resolution of the dissection sites. The patient's cardiovascular risk factors included mild smoking and high total cholesterol and low-density-lipoprotein-cholesterol levels, which showed a marked fall after pregnancy without pharmacological cholesterol-modifying therapy raising the question whether pregnancy-related hypercholesterolemia contributed to the pathogenesis of pregnancy-associated spontaneous coronary artery dissection (P-SCAD). In a systematic review of the literature, 16 women [median age 34 (31-36.5) years] with P-SCAD and angiographic follow-up were identified. The majority (69%) of P-SCAD cases occurred postpartum [median time after delivery: 13 (7-21) days]. In 10/16 (63%) patients medical treatment including betablocker and antiplatelet therapy was given leading to complete resolution of the dissection in 5 of them (31% of all patients) at follow-up, whereas in the other 5 patients the dissections were persisting or even progressive. Of the medically treated patients, 80% were free of symptoms suggestive for ischemia at follow-up. In 5/16 patients percutaneous coronary intervention (PCI) was performed as first-line therapy. Three patients underwent coronary artery bypass grafting, which was performed primarily in one patient, and secondarily in two patients with persisting dissections and ongoing ischemic symptoms after previous medical treatment or PCI without stenting, respectively. In conclusion, medical treatment including ASA, clopidogrel and betablocker therapy results in an excellent clinical and angiographic result in approximately one third of patients with P-SCAD.

Adult↗

Time course of serial cystatin C levels in comparison with serum creatinine after application of radiocontrast media.

BACKGROUND: The delayed increase of creatinine after radiocontrast application is a potential reason for overlooking radiocontrast nephrotoxicity. Cystatin C may be more useful to rapidly assess a decrease in glomerular filtration rate (GFR). We compared cystatin C and creatinine to examine their kinetics after application of radiocontrast media. PATIENTS AND METHODS: Forty-one patients (60.8 +/- 8.8 years, 68% males) with normal to subnormal GFR scheduled for coronary angiography (27% with angioplasty), were studied for serum cystatin C and creatinine levels before, 5 h, 24 h and 48 h after angiography. Furthermore, alpha1-microglobulin was checked for evidence of tubular damage. RESULTS: At 5 hours after angiography, there was no significant change compared to baseline in either serum creatinine nor cystatin C. In comparison with the value immediately before coronary angiography, the increase of cystatin C achieved a maximum at 24 h after the application of the contrast agent (+7.2%). Within 48 h, cystatin C decreased to the level before angiography. Serum creatinine increased at 24 h (+7.7%) and continued to increase at 48 h (+11.3%). CONCLUSION: Cystatin C increases earlier after radiocontrast application compared with creatinine. Therefore, cystatin C needs to be investigated as a potential early marker for nephrotoxicity, especially in the upcoming setting of short-time hospitalizations for coronary angiographies and interventions. Thus, further studies in patients with renal failure undergoing radiocontrast application are warranted to assess the usefulness of cystatin C in respect of an earlier detection of radiocontrast nephrotoxicity.

Aged↗

[A case of coronary vasospasm treated with stent placement].

We report about a 49 year old woman with repeated chest pain at rest. During hyperventilation significant ST-segment elevation in leads V1-V5 appeared. Bicycle stress test did not provoke any ECG changes. Coronary angiography showed a significant stenosis of the left anterior descending coronary artery. Successful balloon angioplasty followed by stent implantation was performed. After an uneventful course of twelve months, hyperventilation could provoke neither chest pain nor ECG changes again without any antispastic medical treatment. Impact of fixed atherosclerotic lesions for the occurrence of coronary vasospasm, usefulness of hyperventilation as a non-invasive provocation test and therapy are discussed.

Angina Pectoris, Variant↗

[Spontaneous coronary artery dissection as a rare cause of an acute coronary syndrome].

Spontaneous coronary artery dissection is a rare cause of an acute coronary syndrome. This report describes a previously healthy woman without cardiovascular risk factors who presented with an acute anterior non-ST elevation myocardial infarction. Coronary angiography revealed an isolated longitudinal dissection in the middle part of the left anterior descending coronary artery (LAD) with normal flow of the contrast media. The patient was treated conservatively with heparin, aspirin, clopidogrel, and beta-receptor blocker. Stress exercise test was normal at discharge. After an event-free follow-up of three and a half months coronary angiography showed a completely normal LAD. Literature about epidemiology, pathogenesis, diagnosis and treatment of spontaneous coronary artery dissection is reviewed.

Adrenergic beta-Antagonists↗

Symptomatic mechanical heart valve thrombosis: high morbidity and mortality despite successful treatment options.

BACKGROUND: Recommendations for treatment of mechanical prosthetic heart valve thrombosis (PVT) include systemic thrombolysis and/or reoperation. Data on complications and outcome are limited. METHODS: Clinical and echocardiographic findings of 17 patients with mechanical PVT were reviewed. Complications and outcome of surgery and/or thrombolysis were analysed. Prospective follow-up was obtained. RESULTS: Symptomatic PVT occurred 8.4 +/- 7.2 years after mechanical valve replacement at mean age 55 +/- 15 years. Thrombosis involved the mitral valve in 12 patients (71%), the aortic valve in 4 (24%) and the tricuspid valve in one (6%). The reason for PVT was inadequate anticoagulation in 11 patients (65%), endomyocardial fibrosis in 2 (12%) and unknown in 4 (24%). Prior to diagnosis, systemic emboli occurred in 6 patients (35%). Thirteen patients (76%) presented in functional class NYHA IV. Haemodynamic valve obstruction was documented by echocardiography in 15 patients (88%). Treatment included primary reoperation in 12 patients (71%), thrombolysis with urokinase in 3 (18%) (with reoperation in 1), reinstitution of adequate anticoagulation in one (6%); death occurred before treatment in one (6%). Intraoperatively, both pannus and thrombus were found in 5 of 13 patients (38%). Treatment-related emboli occurred in 5 patients (29%), to the brain in 3, to the legs in one and to a coronary artery in one. Five patients died (mortality 29%) within 30 days due to multiorgan failure/septicaemia (3 patients), congestive heart failure (1), or cerebral emboli (1). Follow-up after 28 +/- 28 months in the 12 surviving patients was unremarkable. CONCLUSIONS: The most common aetiology for obstructive PVT is thrombus formation due to inadequate anticoagulation. PVT remains a serious complication with high morbidity and mortality despite aggressive treatment by thrombolysis and/or surgery. Surgery is often needed due to the frequent presence of pannus and/or large thrombi. However, long-term prognosis after successful treatment of PVT is excellent.

Adult↗

Malfunction of a unipolar pacemaker system following development of marked subcutaneous emphysema.

Failure of a unipolar pacemaker system due to subcutaneous emphysema is a rare but potentially life-threatening complication after implantation. We report on a pacemaker dysfunction observed three days after implantation in a 91-year-old patient following development of marked subcutaneous emphysema. Function was immediately restored following application of pressure bandages and the condition resolved within a few days.

Aged↗

Early sheath removal after coronary artery interventions with use of a suture-mediated closure device: clinical outcome and results of Doppler US evaluation.

PURPOSE: To evaluate the safety and efficacy of a suture-mediated closure device by comparing clinical outcomes of its use to those of manual compression and by using Doppler ultrasound (US) examination. MATERIALS AND METHODS: One hundred patients were randomized to treatment with either suture-mediated closure (n = 50) or manual compression (n = 50) after percutaneous transluminal coronary angioplasty (PTCA). The 50 patients randomized to receive suture-based treatment were allowed to get out of bed 4 hours after the procedure, whereas bed rest was required for 1 day in the patients treated with manual compression. All patients underwent clinical and US examination before getting out of bed and before discharge from the hospital. RESULTS: Forty-seven of 50 patients randomized to undergo suture-mediated closure were ambulatory the day of intervention, in 6.2 hours +/- 4.7 (mean +/- SE) after undergoing PTCA. The results of the US examination for these patients demonstrated the absence of bleeding complications after getting out of bed. All patients treated with use of manual compression were ambulatory the following day, 18.3 hours +/- 2.2 after undergoing PTCA. There was no difference in the occurrence of vascular complications between the two groups. CONCLUSION: Suture-based closure is a safe and effective method of achieving immediate hemostasis and shorter bed rest without increasing the risk of bleeding complications in PTCA procedures.

Angioplasty, Balloon, Coronary↗

Left ventricular end-diastolic pressure can be estimated by either changes in transmitral inflow pattern during valsalva maneuver or analysis of pulmonary venous flow.

We directly compared the transmitral inflow pattern during preload reduction and pulmonary venous flow velocities to determine left ventricular end-diastolic pressure (LVEDP) in 78 patients who underwent left heart catheterization. Transmitral inflow indexes (A-wave duration, ratio of peak flow velocity of early diastole [E] to peak flow velocity of late diastole during atrial contraction [A] [E/A ratio]) at rest and during the Valsalva maneuver (30 mm Hg for 15 seconds) and indexes of pulmonary venous flow (velocity and duration of the atrial reversal) were obtained. Fair correlations existed between LVEDP (mean 15+/-6 mm Hg) and the percentage decrease in the E/A ratio (r = 0.72), increase in duration of A wave during the Valsalva maneuver (r = 0.60), flow velocity of atrial reversal (r = 0.58), and difference of duration of atrial flow reversal and A wave (r = 0.62) (all P<.001). While sensitivity, specificity, and diagnostic accuracy to detect an elevated LVEDP were comparable, technically adequate Doppler recordings were obtained more often for the mitral inflow during the Valsalva maneuver than for the pulmonary venous flow (72 versus 66 patients, P< 0.05).

Aged↗

Importance of ventricular rate after mode switching during low intensity exercise as assessed by clinical symptoms and ventilatory gas exchange.

Automatic mode switching from DDD(R) to DDI(R) or VVI(R) pacing modes has improved dual chamber pacing in patients at high risk for supraventricular tachyarrhythmias. However, little is known about the effect of ventricular pacing rate adaptation after mode switching. We conducted a single-blinded, crossover study in 15 patients (58 +/- 21 years) with a DDD pacemaker who had AV block and normal sinus node function to investigate the influence of pacing rate adaptation to intrinsic heart rate during low intensity exercise. Patients performed two tests (A/B) of low intensity treadmill exercise (0.5 W/kg) in randomized order. They initially walked for 6 minutes while paced in DDD mode. The pacing mode was then switched to VVI with a pacing rate of either 70 beats/min (test A) or matched to the intrinsic heart rate (95 +/- 11 beats/min test B). Respiratory gas exchange variables were determined and patients classified the effort before and after mode switching on a Borg scale from 6 to 20. Percentage changes of respiratory gas exchange measurements were significantly larger (O2 consumption: -8.2 +/- 5.0% vs. -0.6 +/- 7.2%; ventilatory equivalent of CO2 exhalation: 5.3 +/- 4.9% vs. 1.5 +/- 4.3%; respiratory exchange ratio: 7.0 +/- 2.2% vs. 3.5 +/- 3.0%; end-tidal CO2: -5.7 +/- 2.9% vs. -1.8 +/- 2.7%; all P < 0.01) and the increase in subjective assessment of the effort tended to be higher (mean increase on Borg scale: 1.6 +/- 1.9 vs. 1.1 +/- 1.8, P = 0.07) after heart rate unadjusted than after adjusted mode switching. Mode switching from DDD to VVI pacing is better tolerated and gas exchange measurements are less influenced if ventricular pacing rate is adjusted to the level of physical activity. Thus, pacing rate adjustment should be considered as part of automatic mode switch algorithms.

Adolescent↗

Importance of AV synchronous pacing during low intensity exercise evaluated by oxygen kinetics.

It has been shown that dual chamber pacing with preservation of AV synchrony (DDD) is superior to fixed rate ventricular (VVI) or rate responsive ventricular (VVIR) pacing modes, as evaluated by ventilatory response to exercise. Previous studies have focused on the benefits of maintained AV synchrony at maximal exercise. However, there are limited data comparing O2 kinetics in different pacing modes during low intensity exercise, representing the majority of daily activities. This study aimed to provide an evaluation of different pacing modes using O2 kinetics during low intensity exercise. Nineteen patients (age 61 +/- 18 years) with complete AV block underwent low intensity treadmill exercise (35 W) with simultaneous evaluation of symptoms and O2 kinetics in three pacing modes. The first test was performed in DDD mode followed by a second test in VVIR mode with a programmed heart rate corresponding to the sinus rate during the first test. After 6 minutes of each test, the mode was switched from DDD to VVIR and vice versa. The third test was performed in VVI mode at 70 beats/min. O2 kinetics were defined as O2 deficit (time [rest to steady state] x delta VO2-sigma VO2 [rest to steady state]) and mean response time (MRT) of oxygen consumption (O2 deficit/delta VO2). The O2 deficit was 551 +/- 134 mL in DDD pacing, 634 +/- 139 mL in VVIR pacing, and 648 +/- 179 mL in VVI pacing (P = 0.001). MRT was 49 +/- 7.8 seconds in DDD pacing, 54.7 +/- 9.5 seconds in VVIR pacing, and 57.4 +/- 11.0 seconds in VVI pacing (P = 0.002). Ten (53%) patients developed symptoms during switch from DDD to VVIR mode whereas the switch from VVIR to DDD mode was not perceived by any patient (P < 0.001). In conclusion, our study shows an impact of AV synchronous pacing and heart rate adaptation on O2 kinetics during low intensity exercise that correspond to casual daily life activities. Our observations may have clinical implications for the management of patients with complete AV block.

Atrioventricular Node↗

Characteristics and prognosis of myocardial infarction in patients with normal coronary arteries.

STUDY OBJECTIVES: Myocardial infarction with angiographically normal coronary arteries (MINC) is a life-threatening event with many open questions for physicians and patients. There are little data concerning the prognosis for patients with MINC. DESIGN: Retrospective follow-up study. SETTING: Tertiary referral center. PATIENTS: Patients with MINC were investigated and compared to age- and sex-matched control subjects with myocardial infarction due to coronary artery disease (CAD). The patients were examined clinically using stress exercise and hyperventilation tests. Migraine and Raynaud's symptoms were determined by means of a standardized questionnaire. Serum lipoproteins; the seroprevalence of cytomegalovirus, Helicobacter pylori, and Chlamydia pneumoniae infections; and the most frequent causes of thrombophilia were assessed. MEASUREMENTS AND RESULTS: From > 4,300 angiographies that were performed between 1989 and 1996, 21 patients with MINC were identified. The mean +/- SD patient age at the time of myocardial infarction was 42 +/- 7.5 years. When compared to control subjects (n = 21), patients with MINC had fewer risk factors for CAD. In contrast, MINC patients had more frequent febrile reactions prior to myocardial infarction (six patients vs zero patients; p < 0.05), and the migraine score was significantly higher (7.1 +/- 6.3 vs 2.2 +/- 4.1; p < 0.01). The seroprevalence of antibodies against cytomegalovirus, C pneumoniae, and H pylori tended to be higher in patients with MINC and CAD as compared to matched healthy control subjects. Three patients with MINC vs none with CAD had coagulopathy. During follow-up (53 +/- 37 months), no major cardiac event occurred in the MINC group; no patients with MINC vs nine with CAD (p = 0.0001) underwent repeated angiography. CONCLUSION: High migraine score and prior febrile infection together with a lower cardiovascular risk profile are compatible with an inflammatory and a vasomotor component in the pathophysiology of the acute coronary event in MINC patients. The prognosis for these patients is excellent.

Adult↗

Oxygen uptake to work rate relation throughout peak exercise in normal subjects: relevance for rate adaptive pacemaker programming.

The oxygen uptake to work rate (VO2/WR) relationship observed throughout peak exercise testing is already being applied for rate adaptive pacemaker programming. However, the detailed curve design of VO2/WR with respect to the anaerobic threshold (AT) has not yet been investigated. It was the purpose of this study to determine the VO2/WR slope below and above the AT in a healthy control group. Seventy-eight healthy control subjects (45.9 +/- 17.4 years; 34 women: 49.9 +/- 18.6 years 44 men: 43.6 +/- 16.6 years) were exercised on a treadmill with "breath-by-breath" gas exchange monitoring using the symptom limited "ramping incremental treadmill exercise" (RITE) protocol. The slope of the VO2/WR relationship from rest to peak exercise (r-p), rest to AT (slope A), and AT to peak exercise (slope B) in mL oxygen uptake per watt of external treadmill work was determined by linear regression analysis. [table: see text] The oxygen uptake to work rate relationship throughout peak exercise in the entire study group generated a significant slope change at the AT (31%, P < 0.0001) with a decreasing slope during higher work load intensities. Female subjects demonstrated a greater percentage of slope change at AT (43%), as compared to men (22%, P < 0.01). When using the oxygen uptake to work rate relationship for the programming of the pacemaker's rate response to exercise, the significant slope change at the AT should be considered to more appropriately pace during higher work intensities supported by anaerobic metabolism. Female pacemaker patients should be programmed to generate a steeper VO2/WR slope below AT with a greater slope change at AT, as compared to men. Abnormally high oxygen uptake to work rate ratios above the AT may be possibly used as an indicator of overpacing.

Adult↗