R. Klautz - Academia.edu (original) (raw)

Papers by R. Klautz

The Journal of Thoracic and Cardiovascular Surgery, 1994

Inhibition of the fetal stress response improves cardiac output and gas exchange after fetal card... more Inhibition of the fetal stress response improves cardiac output and gas exchange after fetal cardiac bypass Cardiac bypass in late-gestation fetal lambs causes severe placental vasoconstriction, which leads to fetal death from hypoxemia and respiratory acidosis. This response can be blocked by the administration of indomethacin; however, a fatal metabolic acidosis then graduaUy develops in the fetus. Because the fetus is known to mount an intensive catecholamine response to stress, and because the fetal myocardium is particularly sensitive to increased afterload, we hypothesized that elevated afterload as a result of fetal stress contributes to diminished cardiac output after bypass. Twenty fetal lambs at 80 % gestation underwent 30 minutes of normothermic cardiac bypass at ftow rates of 200 to 500 m1jkg per minute. AU ewes received general anesthesia with ketamine. In 10 fetuses general anesthesia was specificaUy designed not to inhibit the release of stress-related catechols (ketamine); the remaining 10 fetuses received a "high" (cisterna magna) total spinal anesthetic with tetracaine, to block the fetal stress response. In each anesthetic group, 5 of the 10 lambs received indomethacin. During operation, normal hemodynamics were preserved in the spinal anesthetic group. Cardiac output, placental blood ftow, and arterial carbon dioxide tension were aU improved relative to results in the ketamine group. When spinal anesthesia and indomethacin are both given, hemodynamics also approach normal after bypass, and gas exchange is further improved. These data suggest that the inhibition of the stress response by spinal anesthesia improves the hemodynamic status of the fetus during operation and, in combination with indomethacin, allows maintenance of near-normal placental function after fetal cardiac bypass. Similar responses may also be possible in human fetuses with use of a high-dose narcotic technique.

EBioMedicine, 2015

Background: Prolonged or excessive blood loss is a common complication after cardiac surgery. Blo... more Background: Prolonged or excessive blood loss is a common complication after cardiac surgery. Blood remnants and clots, remaining in the pericardial space in spite of chest tube drainage, induce high fibrinolytic activity that may contribute to bleeding complications. Continuous postoperative pericardial flushing (CPPF) with an irrigation solution may reduce blood loss by preventing the accumulation of clots. In this pilot study, the safety and feasibility of CPPF were evaluated and the effect on blood loss and other related complications was investigated. Methods: Between November 2011 and April 2012 twenty-one adult patients undergoing surgery for congenital heart disease (CHD) received CPPF from sternal closure up to 12 h postoperative. With an inflow Redivac drain that was inserted through one of the chest tube incision holes, an irrigation solution (NaCl 0.9% at 38°C) was delivered to the pericardial cavity using a volume controlled flushing system. Safety aspects, feasibility issues and complications were registered. The mean actual blood loss in the CPPF group was compared to the mean of a retrospective group (n = 126). Results: CPPF was successfully completed in 20 (95.2%) patients, and no method related complications were observed. Feasibility was good in this experimental setting. Patients receiving CPPF showed a 30% (P = 0.038) decrease in mean actual blood loss 12 h postoperatively. Conclusions: CPPF after cardiac surgery was found to be safe and feasible in this experimental setting. The clinically relevant effect on blood loss needs to be confirmed in a randomized clinical trial.

Journal of the American College of Cardiology, 2015

Background: Patients with acute aortic dissection type A (AADA) who survive the initial hospital ... more Background: Patients with acute aortic dissection type A (AADA) who survive the initial hospital admission have an impaired long term survival and increased risk of aortic reoperation. The present study assessed whether increased growth of the descending thoracic aorta (DTA) influences survival free from reoperation in AADA patients. methods: A total of 49 patients (58 ± 11 years, 59% male) who underwent surgery for AADA between 2002 and 2013 and had ≥2 postoperative MDCT scans ≥6 months apart were included in the present analysis. Volumetric analysis of the DTA between the left subclavian artery and the level of the apex of the heart was performed (Figure). Average growth rate in ml/year was obtained using linear regression analysis. Survival analysis was performed to assess mid-term freedom from the combined endpoint (death or reoperation on the aorta). results: The mean postoperative DTA volume was 132 ± 57 ml. Linear regression analysis showed an average growth rate of 6.4 ml/year (95% confidence interval: 3.2-9.5 ml/year, p<0.001). Patients with aortic growth <6.4 ml/year were compared to patients with aortic growth ≥6.4 ml/year. Kaplan Meier survival analysis indicated that patients with aortic growth of ≥6.4 ml/year (5 year: 62 ± 15%) had impaired survival free from aortic reoperation compared to patients with aortic growth <6.4 ml/year (5 year: 96 ± 4%; log rank: p=0.006). conclusion: Growth of the DTA ≥6.4 ml/year after AADA is associated with impaired survival free from reoperation on the aorta.

Pflügers Archiv, 1993

It has been shown that in the intact canine heart the lefl-ventricular end-systolic pressure/volu... more It has been shown that in the intact canine heart the lefl-ventricular end-systolic pressure/volume relation (ESPVR) depends on loading conditions: an increase in arterial vascular resistance causes a leftwards shift and a steeper slope of the ESPVR, suggesting an increased inotropic state. Our purpose was to investigate the possible contribution of the sympathetic nervous system to this load sensitivity of the ESPVR, using intact, but denervated, hearts with normal coronary perfusion and afterload. We used two types of loading intervention: venous volume infusion and gradual occlusion of the descending aorta. ESPVRs were obtained in six anaesthetized open-chest dogs, both before and after bilateral ablation of the stellate ganglia. To exclude the influence of heart rate changes, bilateral vagotomy was performed and the heart was paced. The absence of (unpaced) heart rate changes in response to pressure alterations was used to confirm total denervation. Left ventricular pressure was measured with a micromanometer and volume with a conductance catheter. ESPVRs were essentially linear and characterized by their slope (Ees) and volume intercept at 12 kPa (712). We found that Ees (P < 0.0001) and V12 (P < 0.05) were both significantly different during pressure and volume interventions (0.67 + 0.29 and 0.41 ___ 0.18 kPa/ml for Ee~ and 16.2 _+ 8.2 and 18.2 + 8.4 ml for 712 respectively). Denervation did not significantly affect the parameters of the ESPVR obtained by either volume infusion or aortic occlusion. Two-way analysis of variance revealed no significant interactive effect between denervation and intervention, indicating that the sympathetic nervous system does not influence the load dependency of the ESPVR. The dP/dtma• : EDV relationship behaved similarly. These results suggest that load dependency is an intrinsic property of the myocardium.

Netherlands Heart Journal, 2011

Chronic heart failure is a major healthcare problem associated with high morbidity and mortality.... more Chronic heart failure is a major healthcare problem associated with high morbidity and mortality. Despite significant progress in treatment strategies, the prognosis of heart failure patients remains poor. The golden standard treatment for heart failure is heart transplantation after failure of medical therapy, surgery and/or cardiac resynchronisation therapy. In order to improve patients' outcome and quality of life, new emerging treatment modalities are currently being investigated, including mechanical cardiac support devices, of which the left ventricular assist device is the most promising treatment option. Structured care for heart failure patients according to the most recent international heart failure guidelines may further contribute to optimal decision-making. This article will review the conventional and novel treatment modalities of heart failure.

Pfl�gers Archiv European Journal of Physiology, 1997

Pediatric Research, 1993

Correspondence and reprint requests: F. van Bel. M.D.. Department of Pediat-men& Houston, TX) was... more Correspondence and reprint requests: F. van Bel. M.D.. Department of Pediat-men& Houston, TX) was advanced into the thoracic aorta and rics, Neonatal Unit. University Hospital Leiden. P. 0. Box 9600.2300 RC. Leiden. Situated proximal to the balloon catheter for measurement of The Netherlands. supported in pan by a grant from the Ghisela Thier Foundation, Leiden. instantaneous mean aortic pressure. Both femoral venous cath-Netherlands (R.J.M.K.).

Pediatric Research, 1994

thoracic artery (0.75 mm ID, 1.2 mm OD) and directly into the Leiden, The Netherlands. Supported ... more thoracic artery (0.75 mm ID, 1.2 mm OD) and directly into the Leiden, The Netherlands. Supported by PHS Grant HL 35842. F. van BCI is a recipient of the Ter left atrium (20-gauge i .~. catheter, Becton ~i c k i n s o n , ~o u n t a i n Meulenfund of the Netherlands Academy of ~r t s and Sciences.

The Journal of Thoracic and Cardiovascular Surgery, 1997

Objective: After the Fontan operation the right atrium and, thus, the coronary sinus are connecte... more Objective: After the Fontan operation the right atrium and, thus, the coronary sinus are connected to the pulmonary arterial system, which causes the coronary venous pressure to increase. We investigated the acute effects of elevation of coronary venous pressure on baseline hemodynamics, coronary venous flow, and left ventricular contractility. Methods: In acutely instrumented pigs, during complete right heart bypass and during constant cardiac output, pressure in the right atrium, right ventricle, and coronary sinus was altered by a height-adjustable reservoir. At various levels of coronary venous pressure (up to 4 kPa or up to 30 mm Hg), flow from the reservoir was measured and left ventricular hemodynamics and contractility were measured from catheter-derived left ventricular pressure and (conductance) volume data. Contractility of the left ventricle was assessed by the end-systolic pressure-volume relationship derived during an unloading intervention by adjusting the bypass pump speed. Results: Left ventricular end-diastolic pressure increased slightly (about 5%) with each kJlopascal increase in coronary venous pressure, most likely related to diastolic ventricular interaction. No other changes in hemodynamic parameters occurred. Neither coronary venous flow nor left ventricular contractility was influenced by changes in coronary venous pressure. Imposing myocardial stress with dobutamine, 10 ~g/kg per minute, did not change these findings. Conclusion: Increasing coronary venous pressure to 4 kPa in the intact circulation with intact autoregulation does not affect coronary flow or left ventricular contractility. We found no experimental evidence for the usefulness of diversion of the coronary sinus to the left atrium during Fontan-type operations (

Journal of the American College of Cardiology, 2014

background: It remains unclear whether a transthoracic echocardiography (TTE)-based formula may h... more background: It remains unclear whether a transthoracic echocardiography (TTE)-based formula may help in selecting the graft size during David reimplantation technique for aortic root dilation. methods: Forty-nine patients (47±11 years old, 84% men) who underwent David reimplantation technique were evaluated. Leaflet height and leaflet area TTE-based formulas were developed to select the graft size (Figure).The implanted graft size was based on the David's formula, measuring the leaflet height with surgical callipers. The agreement between these formulas and the eventually implanted graft size was evaluated. In addition, the incidence of <2+ residual aortic regurgitation (AR) for each formula was evaluated. results: The incidence of <2+ residual AR was 76%. Based on TTE-derived formula including the leaflet height, a respective 45%, 39% and 16% of patients received the same, a larger or smaller graft than based on David's formula. Based on TTE-derived formula including the leaflet area, a respective 43%, 24% and 33% of patients received the same, a larger or smaller graft. The incidence of <2+ residual AR in patients who underwent isolated David's procedure and received the same or smaller graft size than recommended by the leaflet height and area TTE-based formulas was 83% and 94%, respectively. conclusion: In patients undergoing David reimplantation technique, graft sizing can be performed with TTE. Leaflet height TTE-based formula recommended more frequently an undersized graft than leaflet area.

Journal of the American College of Cardiology, 1995

Objectives. We undertook the present study to determine whether afterload and contractility inter... more Objectives. We undertook the present study to determine whether afterload and contractility interact in the hearts of newborn lambs. We specifically investigated whether stepwise increases in afterload increase contractility. Background. Several studies in the isolated and intact adult dog heart have shown that afterload and contractility are not independent determinants of cardiac performance; rather, they interact. Afterload and contractility are unlikely to interact in the newborn heart because the factors that may mediate the interaction in the adult are missing in the newborn. Methods. We measured contractility at different steady state levels of afterload in seven newborn lambs under complete anesthesia. Contractility was measured by three different indexes: end-systolic pressure-volume relations (slope and volume position); preload-corrected first derivative of left ventricular pressure (dP/dtma,,); and preload-corrected stroke work. Left ventricular pressure and volume were measured with a micromanometer and conductance catheter, respectively. Preload and afterload were manipulated by inflating or deflating a balloon catheter in the inferior vena cava and descending thoracic aorta, respectively. Data are expressed as mean value-+ 1 SD. Results. Stepwise increases in afterload increased contractility, independent of which of the three indexes was used. The slope of the end-systolic pressure-volume relation increased from a mean baseline value of 4.44 + 2.43 to 6.69-+ 2.89 kPa/ml at the highest level of afterioad. Concomitantly, volume at 14 kPa of the endsystolic pressure-volume relation decreased from 3.34-+ 1.52 ml at baseline to 1.12-+ 0.83 ml at the highest afterload. The other two indexes showed qualitatively similar changes. Beats selected from unloading interventions on the basis of the same end-diastolic volume for each level of afterload showed no difference in stroke volume. Conclusions. This study in newborn lambs demonstrates that stepwise increases in afterload increase contractility considerably and that this enables the heart to maintain stroke volume at diferent levels of afterload. This forms direct evidence for the existence of homeometric autoregulation in the intact newborn heart.

JACC: Cardiovascular Imaging, 2010

European Heart Journal, 1992

Evaluation of ventricular performance by the end-systolic pressure-volume relationship (ESPVR) ha... more Evaluation of ventricular performance by the end-systolic pressure-volume relationship (ESPVR) has been extensively performed in the adult heart using the conductance technique. We undertook this study to validate the conductance technique and to generate ESPVRs in the small heart. To validate the technique, we simultaneously measured left ventricular volume by the conductance catheter and biplane cineangiography in nine piglets during changes in volume and contractility. Raw conductance volumes correlated highly with cineangiographic volumes (R = 0.97), and the slope was near identity (1.11 +/- 0.04). However, &amp;#39;alpha Vc-corrected&amp;#39; volumes correlated less well (R = 0.85), probably because of errors induced by the saline technique for alpha Vc. We evaluated the ESPVR in nine lambs by inferior vena cava (IVC) occlusion, aortic occlusion, and volume infusion at rest and during changes in contractility. Reliable and linear ESPVRs were obtained in almost all IVC and aortic occlusions but not in volume infusions. Neither slope (Ees) nor position (V14) significantly changed over time or with dobutamine, but both changed after propranolol, supporting studies showing a limited contractile reserve in the newborn. However, Ees was 25% less steep when generated by IVC occlusion as compared to aortic occlusion. We conclude that the ESPVR can be reliably generated in the small heart using the conductance technique, but that it is sensitive to the loading technique.

$Research paper thumbnail of Strain analysis in patients with severe aortic stenosis and preserved left ventricular ejection fraction undergoing surgical valve replacement$

European Heart Journal, 2009

To evaluate myocardial multidirectional strain and strain rate (S-and-SR) in severe aortic stenos... more To evaluate myocardial multidirectional strain and strain rate (S-and-SR) in severe aortic stenosis (AS) patients with preserved left ventricular (LV) ejection fraction (EF), using two-dimensional speckle-tracking strain imaging (2D-STI). The long-term effect of aortic valve replacement (AVR) on Sand -SR was also evaluated. Methods and results Changes in LV radial, circumferential, and longitudinal Sand -SR were evaluated in 73 severe AS patients (65 + 13 years; aortic valve area 0.8 + 0.2 cm 2) with preserved LVEF (61 + 11%), before and 17 months after AVR. Strain and strain rate data were compared with data from 40 controls (20 healthy individuals and 20 patients with LV hypertrophy) matched by age, gender, body surface area, and LVEF. Compared with controls, severe AS patients had significantly decreased values of LV Sand -SR in the radial (33.1 + 14.8%, P ¼ 0.2; 1.7 + 0.5 s 21 , P ¼ 0.003), circumferential (215.2 + 5.0%, P ¼ 0.001; 20.9 + 0.3 s 21 , P , 0.0001), and longitudinal (214.6 + 4.1%, P , 0.0001; 20.8 + 0.2 s 21 , P , 0.0001) directions. At 17 months after AVR, LV Sand -SR significantly improved in all the three directions, whereas LVEF remained unchanged (60 + 12%, P ¼ 0.7). Conclusion In severe AS patients, impaired LV Sand -SR existed although LVEF was preserved. After AVR, a significant Sand -SR improvement in all the three directions was observed. These subtle changes in LV contractility can be detected by 2D-STI.

Circulation, 1997

Background Increasing the heart rate of the fetus with cardiac failure caused by complete AV bloc... more Background Increasing the heart rate of the fetus with cardiac failure caused by complete AV block (CAVB) may allow delivery of a full-term, stable neonate with preserved ventricular function. Direct fetal pacing may be a feasible method to achieve this, but the effect of pacing on the structure and function of the rapidly developing fetal heart is unknown. Methods and Results CAVB was created in fetal lambs at 80% gestation by cryoablating the AV node. Epicardial ventricular pacing at 130 bpm was achieved by use of a pacemaker placed under the pectoral muscles. The fetus was returned to the uterus and allowed to continue to term. Ventricular function was assessed 1 week after birth in 7 lambs with CAVB and 10 control lambs. By use of the conductance catheter technique, the end-systolic pressure-volume relationship was determined at different heart rates, pacing conditions, and inotropic states. The contractility was not different between the two groups at their baseline heart rates...

The American Journal of Cardiology, 2010

Restrictive mitral annuloplasty is a surgical treatment option for patients with heart failure (H... more Restrictive mitral annuloplasty is a surgical treatment option for patients with heart failure (HF) and functional mitral regurgitation (MR). However, recurrent MR has been reported at mid-term follow-up. The aim of the present study was to identify the echocardiographic predictors of recurrent MR in patients with HF undergoing mitral annuloplasty. During a mean follow-up of 2.6 ؎ 1.6 years, 109 patients with HF (49% ischemic and 51% idiopathic dilated cardiomyopathy) who had undergone mitral valve repair were followed up (of 122 total patients). The severity of MR was quantified, and the following parameters were measured before intervention and at the mid-term follow-up examination: left ventricular (LV) and left atrial volumes and dimensions, LV sphericity index, mitral annular area, and mitral valve geometry parameters. At mid-term follow-up, 21 patients presented with significant MR (grade 2 to 4), and 88 patients had only MR grade 0 to 1. Both groups of patients had had a similar preoperative MR grade, mitral annular area, and LV volume and dimension. In contrast, patients with recurrent MR had had increased preoperative posterior and anterior leaflet angles, tenting height, tenting area, and LV sphericity index compared to the patients without recurrent MR. Of the different parameters of mitral and LV geometry, the distal mitral anterior leaflet angle (hazard ratio 1.48, 95% confidence interval 1.32 to 1.66, p <0.001) and posterior leaflet angle (hazard ratio 1.13, 95% confidence interval 1.07 to 1.19, p <0.001) were independent determinants of MR at mid-term follow-up. In conclusion, in patients with HF of ischemic or idiopathic etiology and functional MR, distal mitral leaflet tethering and posterior mitral leaflet tethering were associated with recurrent MR after restrictive mitral annuloplasty.