Outcome of patients with double valve surgery between 2009 and 2018 at University Hospital Basel, Switzerland

Background

In isolated mitral valve regurgitation general consensus on surgery is to favor repair over replacement excluding rheumatic etiology or endocarditis. If concomitant aortic valve replacement is performed however, clinical evidence is more ambiguous and no explicit guidelines exist on the choice of mitral valve treatment. Both, double valve replacement (DVR) and aortic valve replacement in combination with concomitant mitral valve repair (AVR + MVP) have been proven to be feasible procedures. In our single-center, retrospective, observational cohort study, we compared the outcome of these two surgical techniques focusing on mortality and morbidity.

Methods

89 patients underwent DVR (n = 41) or AVR + MVP (n = 48) in our institution between 2009 and 2018. Follow-up data was collected using electronic patient records, by contacting treating physicians and by telephone interviews. We used the Kaplan–Meier method to analyze mortality during follow-up and Cox regression to investigate potential predictors of mortality.

Results

During a median follow-up duration of 4.5 [IQR 2.9 to 6.1] years, there was no significant difference in mortality between both cohorts. Thirty days mortality was 6.3% in the DVR and 7% in the AVR + MVP cohort. Overall mortality amounted to 17% for DVR and 23% for AVR + MVP. DVR was the preferred procedure for valve disease of rheumatic etiology and for endocarditis, while in degenerative valves AVR + MVP was predominant. More biological valves were used in the AVR + MVP cohort (p < 0.001) and more mechanical valves were implanted in the DVR cohort. The rate of rehospitalization, deterioration of left ventricular ejection fraction and postoperative complications were equally distributed among the two cohorts.

Conclusion

Our data analysis showed that both DVR and AVR + MVP are safe and feasible options for double valve surgery. Based on our findings we could not prove superiority of one surgical technique over the other. Choosing the appropriate procedure for the patient should be influenced by valve etiology, patients’ comorbidities and the surgeons’ experience.

Trial registration

This was a retrospectively registered trial, registered on April 1st 2018, ClinicalTrials.gov Identifier: NCT03667274.

Abdominal Decompression after Cardiac Surgery: Outcome of 42 Patients with Abdominal Compartment Syndrome

BACKGROUND

Up to 50% of patients in intensive care units develop intraabdominal hypertension (IAH) in the course of medical treatment. If not detected on time and treated adequately, IAH may develop into an abdominal compartment syndrome (ACS) which is associated with a high mortality rate. Patients undergoing cardiac surgery are especially prone to develop ACS due to several risk factors including intraoperative hypothermia, fluid resuscitation and acidosis. We investigated patients who developed ACS after cardiac surgery and analyzed potential risk factors, treatment and outcome.

METHODS

From 2011 to 2016, patients with ACS after cardiac surgery requiring decompressive laparotomy were prospectively recorded. Patient characteristics, details on the cardiac surgery, mortality rate and type of treatment of the open abdomen were analyzed.

RESULTS

Incidence of ACS in cardiac surgery patients was 1.0% (n = 42/4128), with a mortality rate of 57%. Ejection fraction, Euroscore2 as well as the perfusion time are independent risk factors for the development of ACS. The outcome of patients with ACS was independent of elective versus emergency surgery, gender, age, BMI or ASA score. In the 18 surviving patients, fascial closure was achieved in 72% after a median of 9 days.

CONCLUSION

Abdominal compartment syndrome is a rare but serious complication after cardiac surgery with a high mortality rate. Independent risk factors for ACS were identified. Negative pressure wound therapy seems to promote and allow early fascia closure of the abdomen and represents therefore a likely benefit for the patient.

Microplegia versus Cardioplexol® in Coronary Artery Bypass Surgery with Minimal Extracorporeal Circulation: Comparison of Two Cardioplegia Concepts

BACKGROUND

The aim of this study is to compare the combined use of the Myocardial Protection System and our microplegia (Basel Microplegia Protocol) with Cardioplexol^® in coronary artery bypass grafting using the minimal extracorporeal circulation.

METHODS

The analysis focused on propensity score matched pairs of patients in whom microplegia or Cardioplexol^® was used. Primary efficacy endpoints were high-sensitivity cardiac troponin-T on postoperative day 1 and peak values during hospitalization. Furthermore, we assessed creatine kinase and creatinine kinase-myocardial type, as well as safety endpoints.

RESULTS

A total of 56 patients who received microplegia and 155 patients who received Cardioplexol^® were included. The use of the microplegia was associated with significantly lower geometric mean (confidence interval) peak values of high-sensitivity cardiac troponin-T (233 ng/L [194-280 ng/L] vs. 362 ng/L [315-416 ng/L]; p = 0.001), creatinine kinase (539 U/L [458-633 U/L] vs. 719 U/L [645-801 U/L]; p = 0.011), and creatinine kinase-myocardial type (13.8 µg/L [9.6-19.9 µg/L] vs. 21.6 µg/L [18.9-24.6 µg/L]; p = 0.026), and a shorter length of stay on the intensive care unit (1.5 days [1.2-1.8 days] vs. 1.9 days [1.7-2.1 days]; p = 0.011). Major adverse cardiac and cerebrovascular events occurred with roughly equal frequency (1.8 vs. 5.2%; p = 0.331).

CONCLUSIONS

The use of the Basel Microplegia Protocol was associated with lower peak values of high-sensitivity cardiac troponin-T, creatinine kinase, and creatinine kinase-myocardial type and with a shorter length of stay on the intensive care unit, as compared with the use of Cardioplexol^® in isolated coronary artery bypass surgery using minimal extracorporeal circulation.

Clinical implementation of a novel myocardial protection pathway in coronary artery bypass surgery with minimal extracorporeal circulation

INTRODUCTION

The aim of this study was to report the clinical implementation of the joint use of the Myocardial Protection System (MPS^®) and the minimal extracorporeal circulation system (MiECC), in conjunction with an institutionally refined dose/volume-dependent microplegia in coronary artery bypass grafting (CABG).

METHODS

Patients with isolated CABG surgery were included. The final protocol to achieve cardioplegic arrest consisted of warm blood cardioplegia with 20 mmol potassium (K), 1.6 g magnesium (Mg) and 40 mg lidocaine per liter (L) blood. We prospectively collected intra- and postoperative data to monitor and validate this novel approach.

RESULTS

Eighty patients were operated accordingly. Mean (SD) aortic clamping time and extracorporeal perfusion time were 67.5 (22.6) and 101.1 (31.9) minutes, respectively. Failure to induce cardiac arrest was seen in six patients at the early stage of refinement of the formula. Median (IQR) high -sensitivity cardiac troponin T (hs-cTnT) on the first postoperative day (POD) and peak hs-cTnT were 262.5 ng/L (194.3-405.8) and 265.5 ng/L (194.3-405.8), respectively. Median (IQR) creatine kinase-myocardial type (CK-MB) on POD 1 and peak CK-MB were 14.2 µg/L (10.5-22.7) and 14.2 µg/L (10.7-23.2), respectively. Median (IQR) creatine kinase (CK) on POD 1 and peak CK were 517.5 U/L (389.3-849.8) and 597.5 U/L (455.0-943.0), respectively. No patient died during hospitalization.

CONCLUSIONS

The combination of this cardioplegic formula with MPS^® and MiECC in CABG was safe and feasible. With the final chemical makeup, cardiac arrest was reliably achieved. Remarkably low postoperative cardiac markers indicate shielded cardiac protection during surgery.

Paracrine potential of adipose stromal vascular fraction cells to recover hypoxia-induced loss of cardiomyocyte function

Cell-based therapies show promising results in cardiac function recovery mostly through paracrine-mediated processes (as angiogenesis) in chronic ischemia. In this study, we aim to develop a 2D (two-dimensional) in vitro cardiac hypoxia model mimicking severe cardiac ischemia to specifically investigate the prosurvival paracrine effects of adipose tissue-derived stromal vascular fraction (SVF) cell secretome released upon three-dimensional (3D) culture. For the 2D-cardiac hypoxia model, neonatal rat cardiomyocytes (CM) were cultured for 5 days at < 1% (approaching anoxia) oxygen (O₂ ) tension. Typical cardiac differentiation hallmarks and contractile ability were used to assess both the cardiomyocyte loss of functionality upon anoxia exposure and its possible recovery following the 5-day-treatment with SVF-conditioned media (collected following 6-day-perfusion-based culture on collagen scaffolds in either normoxia or approaching anoxia). The culture at < 1% O ₂ for 5 days mimicked the reversible condition of hibernating myocardium with still living and poorly contractile CM (reversible state). Only SVF-medium conditioned in normoxia expressing a high level of the prosurvival hepatocyte-growth factor (HGF) and insulin-like growth factor (IGF) allowed the partial recovery of the functionality of damaged CM. The secretome generated by SVF-engineered tissues showed a high paracrine potential to rescue the nonfunctional CM, therefore resulting in a promising patch-based treatment of specific low-perfused areas after myocardial infarction.

Case report: Open replacement of incomplete semi-circular traumatic ruptures of the ascending and descending aorta

An incomplete traumatic rupture of the ascending aorta is a rare but life-threatening condition. Hence, the assessment of the extent of the injury prior to therapy is crucial. We report a case of a 50-year-old male with traumatic aortic rupture who underwent emergency surgery after the evaluation of computed tomography scan (CT-scan). The surgical treatment involved replacement of the ascending aorta and stent implantation in descending aorta due to its covered rupture.

Automated fastener versus manually tied knots in minimally invasive mitral valve repair: impact on operation time and short- term results

Background

This study compares the influence of two different annuloplasty attachment suture applications, namely the use of an automated fastener versus manually tied knots using a traditional knot pusher, on total operation time, on cardiopulmonary-bypass time and on cross-clamp time, and on short-term outcome.

Methods

Sixty patients underwent isolated minimally invasive mitral valve repair in Carpentier Type-II mitral disease with implantation of an annuloplasty ring in combination with correction of the prolapsing leaflet using artificial chords. The first 30 patients after implementation of a novel automated fastener were compared with the last 30 patients corrected with a traditional knot pusher. No significant differences with regard to demographic data (age, gender, NYHA class, ejection fraction, BMI, cardiovascular risk factors) between the two groups were found. All patients received isolated mitral valve repair in the first run. Bretschneider HTK was used for cardioplegic cardiac arrest in all patients.

Results

Transesophageal and transthoracic echocardiography at the end of operation and at discharge revealed no (n = 25), trace (n = 28) or mild (n = 7) residual regurgitation with no evidence of ring dehiscence and without any significant clinical differences between the groups. Cross-clamp, cardiopulmonary-bypass and total- operation time were significantly reduced in the automated fastener group compared to the group using a traditional knot pusher (87.1 ± 17.9 vs. 101.3 ± 17.8; p < 0.01, 138.1 ± 25.6 vs. 152.7 ± 24.9; p < 0.05, and 203.9 ± 31.02 vs. 223.8 ± 29.01; p < 0.01, respectively).

Conclusion

Our short-term results indicate a safe, reliable and fast application of the novel automated fastener device in combination with significant time savings in cardioplegic arrest and cardiopulmonary bypass.

One-year patency control and risk analysis of eSVS®-mesh-supported coronary saphenous vein grafts

Background

The eSVS® external venous nitinol mesh (Kips Bay Medical, Minneapolis, USA) was designed to improve long-term patency of coronary saphenous vein grafts (SVG) by preventing pressure-induced wall stress and reactive neo-intimal hyperplasia. We present one-year-patency rates of meshed SVGs assessed by coronary computed tomographic angiography (cCTA).

Patients and Methods

Data from consecutive patients receiving an eSVS® meshed coronary bypass SVG from 06/2010 to 06/2011 were prospectively collected and analysed post-hoc. Patient characteristics, coronary artery disease, SVG quality, surgery (including number of anastomoses and transit time flow-measurement: TTFM), postoperative course and graft patency by cCTA were recorded. Potential risk factors for meshed graft occlusion were evaluated.

Results

22 patients received an eSVS® mesh (18 isolated CABG, 4 combined with aortic valve replacement). Three patients died prior to the one-year follow-up and were excluded. All 19 surviving patients (mean age 70.4 ± 9.5 years, 3 female) completed a cCTA of all grafts at 12 ± 0.1 months after surgery including 21 meshed SVGs (33 distal anastomoses), 7 unmeshed SVGs (13 distal anastomoses) and 22 arterial grafts (30 distal anastomoses).

Mesh application was safe with patent grafts (by intraoperative TTFM) and perioperative course uneventful in all patients. The average graft/anastomosis number per patient was 2.6 ± 0.5/3.7 ± 0.8. Patency was unrestricted in all arterial and unmeshed SVGs (cCTA). Meshed SVG patency was 85 % (n = 28/33) for distal anastomoses and 76 % (n = 16/21) among meshed SVGs. Four SVGs with single distal anastomosis to the right coronary were completely occluded. One sequential graft to the left coronary was occluded between proximal and first distal anastomosis (see Fig. 1). Patency was independent of target site, coronary run-off, SVG quality and sequential distal grafting. All patients were asymptomatic.

Conclusions

The overall one-year patency rate of eSVS® meshed SVGs/anastomoses was 76 %/85 %. Surgical implantation is safe independently of target site, run-off, vein quality and sequential distal anastomoses. However, graft patency of meshed veins (76 %) was inferior to non-meshed (100 %) or arterial grafts (100 %). Thus our mid-term data do not sustain the concept of improving vein graft patency by external reinforcing with the eSVS® mesh. Further long-term follow-up is warranted.

Rapamycin impairs endothelial cell function in human internal thoracic arteries

Background

Definitive fate of the coronary endothelium after implantation of a drug-eluting stent remains unclear, but evidence has accumulated that treatment with rapamycin-eluting stents impairs endothelial function in human coronary arteries. The aim of our study was to demonstrate this phenomenon on functional, morphological and biochemical level in human internal thoracic arteries (ITA) serving as coronary artery model.

Methods

After exposure to rapamycin for 20 h, functional activity of ITA rings was investigated using the organ bath technique. Morphological analysis was performed by scanning electron microscopy and evaluated by two independent observers in blinded fashion. For measurement of endothelial nitric oxide synthase (eNOS) release, mammalian target of rapamycin (mTOR) and protein kinase B (PKB) (Akt) activation, Western blotting on human mammary epithelial cells-1 and on ITA homogenates was performed.

Results

Comparison of the acetylcholine-induced relaxation revealed a significant concentration-dependent decrease to 66 ± 7 % and 36 ± 7 % (mean ± SEM) after 20-h incubation with 1 and 10 μM rapamycin. Electron microscopic evaluation of the endothelial layer showed no differences between controls and samples exposed to 10 μM rapamycin. Western blots after 20-h incubation with rapamycin (10 nM–1 μM) revealed a significant and concentration-dependent reduction of p (Ser 1177)-eNOS (down to 38 ± 8 %) in human mammary epithelial cells (Hmec)-1. Furthermore, 1 μM rapamycin significantly reduced activation of p (Ser2481)-mTOR (58 ± 11 %), p (Ser2481)-mTOR (23 ± 4 %) and p (Ser473)-Akt (38 ± 6 %) in ITA homogenates leaving Akt protein levels unchanged.

Conclusions

The present data suggests that 20-h exposure of ITA rings to rapamycin reduces endothelium-mediated relaxation through down-regulation of Akt-phosphorylation via the mTOR signalling axis within the ITA tissue without injuring the endothelial cell layer.

A new cable-tie-based sternal closure device: infectious considerations

OBJECTIVES

To determine the difference in sternal infection and other infectious events between conventional wire and cable-tie-based closure techniques post-sternotomy in a collective of patients after cardiac surgery.

METHODS

The sternal ZipFix™ (ZF) system consists of a biocompatible poly-ether-ether-ketone (PEEK) cable-tie that surrounds the sternum through the intercostal space and provides a large implant-to-bone contact. Between 1 February 2011 and 31 January 2012, 680 cardiac operations were performed via sternotomy at our institution. After the exclusion of operations for active endocarditis and early mortality within 7 days, 95 patients were exclusively closed with ZF and could be compared with 498 who were closed with conventional wires (CWs) during the same period. A multivariable logistic regression analysis, including body mass index, renal impairment and emergency as suspected confounders and inverse propensity weights was performed on the infection rate.

RESULTS

Total infection rate was 6.1%, with a total of 36 diagnosed sternal infections (5 in ZF and 31 in CW). Comparing ZF with CW with regard to sternal infection, there is no statistically significant difference related to the device (odds ratio: 0.067, confidence interval: 0.04-9.16, P=0.72). The propensity modelling provided excellent overlap and the mean propensity was almost the same in both groups. Thus, we have observed no difference in receiving either ZF or CW. No sternal instability was observed with the ZF device, unlike 4/31 patients in the CW group. The overall operation time is reduced by 11 min in the ZF group with identical perfusion and clamping times.

CONCLUSIONS

Our study underlines a neutral effect of the sternal ZipFix™ system in patients regarding sternal infection. Postoperative complications are similar in both sternal closure methods. The cable-tie-based system is fast, easy to use, reliable and safe.

A new cable-tie based sternal closure system: description of the device, technique of implantation and first clinical evaluation

Background

Wire closure still remains the preferred technique despite reasonable disadvantages. Associated complications, such as infection and sternal instability, cause time- and cost-consuming therapies. We present a new tool for sternal closure with its first clinical experience and results.

Methods

The sternal ZipFix^TM System is based on the cable-tie principle. It primarily consists of biocompatible Poly-Ether-Ether-Ketone implants and is predominantly used peristernally through the intercostal space. The system provides a large implant-to-bone contact for better force distribution and for avoiding bone cut through.

Results

50 patients were closed with the ZipFix^TM system. No sternal instability was observed at 30 days. Two patients developed a mediastinitis that necessitated the removal of the device; however, the ZipFix^TM were intact and the sternum remained stable.

Conclusions

In our initial evaluation, the short-term results have shown that the sternal ZipFix^TM can be used safely and effectively. It is fast, easy to use and serves as a potential alternative for traditional wire closure.

Simplified closure of ministernotomy using thermoreactive sternal clips

An increasing number of aortic valve replacements are performed through a ministernotomy. Due to the small incision and partial fixation of the caudal sternum, the traditional wire closure can be complicated and even harmful to the surrounding tissue. In such cases, we recommend the use of nitinol clips for sternal closure. This technique, which we have used in 48 patients, is simple, safe, and fast, and results in excellent outcomes.

Eyes wide shut--unusual two stage repair of pectus excavatum and annuloaortic ectasia in a 37 year old marfan patient: case report

We report about a 37 year old male patient with a pectus excavatum. The patient was in NYHA functional class III. After performed computed tomography the symptoms were thought to be related to the severity of chest deformation. A Ravitch-procedure had been accomplished in a district hospital in 2009. The crack of a metal bar led to a reevaluation 2010, in which surprisingly the presence of an annuloaortic ectasia (root 73 × 74 mm) in direct neighborhood of the formerly implanted metal-bars was diagnosed. Echocardiography revealed a severe aortic valve regurgitation, the left ventricle was massively dilated presenting a reduced ejection fraction of 45%. A marfan syndrome was suspected and the patient underwent a valve sparing aortic root replacement (David procedure) in our institution with an uneventful postoperative course. A review of the literature in combination with discussion of our case suggests the application of stronger recommendations towards preoperative cardiovascular assessment in patients with pectus excavatum.

Proteome analysis in cardiovascular pathophysiology using Dahl rat model

Dahl salt-sensitive (DS) and salt-resistant (DR) inbred rat strains represent a well established animal model for cardiovascular research. Upon prolonged administration of high-salt-containing diet, DS rats develop systemic hypertension, and as a consequence they develop left ventricular hypertrophy, followed by heart failure. The aim of this work was to explore whether this animal model is suitable to identify biomarkers that characterize defined stages of cardiac pathophysiological conditions. The work had to be performed in two stages: in the first part proteomic differences that are attributable to the two separate rat lines (DS and DR) had to be established, and in the second part the process of development of heart failure due to feeding the rats with high-salt-containing diet has to be monitored. This work describes the results of the first stage, with the outcome of protein expression profiles of left ventricular tissues of DS and DR rats kept under low salt diet. Substantial extent of quantitative and qualitative expression differences between both strains of Dahl rats in heart tissue was detected. Using Principal Component Analysis, Linear Discriminant Analysis and other statistical means we have established sets of differentially expressed proteins, candidates for further molecular analysis of the heart failure mechanisms.

[Surgical treatment options in end-stage heart failure]

Despite significant improvements in pharmacological therapy heart failure is still one of the leading causes for death in the Western World. The gold standard treatment of end-stage heart failure remains cardiac transplantation, but there is a great excess of eligible candidates compared with the low number of suitable donor organs. The variety of surgical organ preserving treatment strategies has significantly increased during the last 20 years, intenting either to delay or even to prevent the need for cardiac transplantation. An individually tailored surgical concept should be considered as an alternative in any heart failure patient who has reached the limits of pharmacologic therapy. This article gives an overview about current and potential future therapeutic options in end-stage heart failure.

Reactive oxygen species mediate functional differences in human radial and internal thoracic arteries from smokers

OBJECTIVE

Smoking not only increases the risk that coronary heart disease will develop but also morbidity and mortality in patients with known coronary atherosclerosis and after coronary artery bypass grafting. Excessive generation of reactive oxygen species (ROS) has been implicated as the final common pathway for the development of endothelial dysfunction in various cardiovascular risk factors. This study assessed the influence of smoking on two different human arteries routinely used as coronary artery bypass graft conduits.

METHODS

Isometric tension was recorded on discarded segments of human left internal thoracic artery (ITA) and the radial artery (RA) from smokers and nonsmokers.

RESULTS

The contractile response to endothelin-1 was significantly stronger in arteries from smokers than in those from nonsmokers. By contrast, endothelium-dependent relaxant responses to acetylcholine were attenuated in RA rings but enhanced in ITA rings from smokers. In additional experiments, 5-(&6)-chloromethyl-2'-7'-dichlorodihydro-fluorescein diacetate (DCDHF) was used to photochemically detect ROS by confocal imaging of intact ITA and RA. Enhanced production of ROS was induced by exposure of tissues to 28 degrees C. While during exposure to 28 degrees C, basal fluorescence emission was unchanged in ITA rings, it increased significantly in RA rings, indicating enhanced formation of ROS in this peripheral artery.

CONCLUSIONS

Data suggest that smoking induces endothelial dysfunction by increasing vascular ROS production. Different levels of endogenous antioxidant enzyme activities and the degree of atherosclerotic changes might modulate physiologic and pharmacologic vasoreactivity and be responsible for decreased graft patency of RA compared with ITA conduits, especially in active smokers.

Activated Rho/Rho kinase and modified calcium sensitivity in cryopreserved human saphenous veins

BACKGROUND

We have shown previously that cryopreservation of human internal mammary arteries activates protein kinase C and enhances intracellular Ca(2+) [Ca(2+)](i). We now present evidence that in human saphenous veins (HSV) cryoinjury is associated with activation of the Rho/Rho kinase signaling pathways and enhanced [Ca(2+)](i).

METHODS

HSV were investigated in vitro either unfrozen within 12h after removal or after storage at -196 degrees C in a cryomedium containing 1.8M dimethyl sulfoxide and 0.1M sucrose as cryoprotectant additives.

RESULTS

Cryostorage diminished responses to receptor-mediated contractile agonists such as noradrenaline, 5-HT and endothelin-1 by up to 30% whereas responses to KCl were attenuated by about 50%. Concentration-response curves for CaCl(2) on unfrozen and cryopreserved HSV revealed similar inhibitory activities of both blocking 1,4-dihydropyridine derivatives nifedipine and the (-)-(R) enantiomer of SDZ 202-791 whereas the Ca(2+) channel activating (+)-(S) enantiomer of SDZ 202-791 was 10 times less effective at enhancing contractions to CaCl(2) when tested after cryostorage. These functional effects were reflected by changes in [Ca(2+)](i) as demonstrated by fluorescence of Fluo-3AM loaded veins. The diminished activity of (+)-(S) SDZ 202-791 in cryopreserved HSV was reversed partially when the potassium channel opener pinacidil (1 microM) was present during the freezing/thawing process. Blockade of Rho kinase by HA-1077 proved to be significantly more effective at attenuating contractile responses to both endothelin-1 and KCl after cryostorage.

CONCLUSIONS

Data suggested that cryopreservation modified [Ca(2+)](i) of venous smooth muscle cells (1) through depolarization-induced changes in Ca(2+) influx and (2) through activation of Rho kinase signaling pathways.

Intraindividual comparison of human radial and internal thoracic arteries in vitro and the effect of preoperative calcium blocker therapy

The patency rate of radial artery (RA) conduits is considerably lower than that of internal thoracic artery (ITA) grafts and the evidence suggests that this is due to a clinically suspected higher incidence of vasospasm. The aim of this study was, therefore, to compare intraindividually the pharmacological reactivity of RA with that of ITA. Both RA and ITA were taken from the same patients and investigated in parallel. Changes in tone were monitored isometrically on ring preparations from both arteries in organ baths with modified Krebs-Henseleit solution containing 1.25 mm calcium chloride at 1 g passive preload. In intraindividual comparisons maximal receptor-mediated contractile responses to noradrenaline and endothelin-1 and endothelium-dependent acetylcholine-induced relaxant responses revealed no differences between both arteries. By contrast, depolarization-induced contractions to potassium chloride (KCl) appeared to be significantly higher in RA than in ITA. Further analysis, however, revealed that this difference was due to preoperative calcium entry blocker (Ca(2+)eB) therapy. Compared with control tissues, maximal responses to KCl were significantly attenuated in the ITA but unchanged in RA when arteries were obtained from patients with preoperative Ca(2+)eB therapy. The present results suggested that functional responses to pharmacological stimuli of both RA and ITA were quite similar. Preoperative Ca(2+)eB therapy, however, attenuated markedly responses to KCl of the ITA leaving those of RA unchanged. These results, demonstrating a lower sensitivity to Ca(2+)eB of RA, therefore suggested that in addition to Ca(2+)eB other classes of drug may be more effective at reducing the propensity of RA conduits to vasospasm.

Impact of freezing/thawing procedures on the post-thaw viability of cryopreserved human saphenous vein conduits

BACKGROUND

Cryopreserved human blood vessels are important tools in reconstructive surgery. However, patency of frozen/thawed conduits depends largely on the freezing/thawing procedures employed.

METHODS

Changes in tone were recorded on rings from human saphenous vein (SV) and used to quantify the degree of cryoinjury after different periods of exposure at room temperature to the cryomedium (Krebs-Henseleit solution containing 1.8M dimethyl sulfoxide and 0.1M sucrose) and after different cooling speeds and thawing rates following storage at -196 degrees C.

RESULTS

Without freezing, exposure of SV to the cryomedium for up to 240 min did not modify contractile responses to noradrenaline (NA). Pre-freezing exposure to the cryomedium for 10-120 min attenuated significantly post-thaw maximal contractile responses to NA, endothelin-1 (ET-1) and potassium chloride (KCl) by 30-44%. Exposure for 240 min attenuated post-thaw contractile responses to all tested agents markedly by 62-67%. Optimal post-thaw contractile activity was obtained with SV frozen at about -1.2 degrees C/min and thawed slowly at about 15 degrees C/min. In these SV maximal contractile responses to NA, ET-1 and KCl amounted to 66%, 70% and 60% of that produced by unfrozen controls. Following cryostorage of veins for up to 10 years the responsiveness of vascular smooth muscle to NA was well maintained.

CONCLUSION

Cryopreservation allows long-term banking of viable human SV with only minor loss in contractility.

[Current evidence-based situation in coronary revascularization--CABG vs. PCI and diabetes?]

A variety of randomized, controlled trials comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) found similar results in mortality but significant differences in number of reinterventions in favor of CABG. This work gives an overview about the relevance and limitations of these studies in line with newly published large scale observational studies, which reveal significantly lower mortality-rates in CABG patients. Emphasis is placed on the special situation in the diabetic patient.

OPCAB surgery after right pneumonectomy

Coronary artery bypass grafting was performed in a 58-year-old patient 3 years after right pneumonectomy for nonsmall cell lung cancer stage IIIa. The CT scan demonstrated a marked shift of the mediastinum into the right chest, but revealed a feasible access to the left coronary artery by median sternotomy. Pulmonary function was impaired. Off-pump coronary artery bypass grafting was performed to avoid cannulation under more difficult conditions and to prevent negative side effects of cardiopulmonary bypass to the pulmonary function. The postoperative recovery was uneventful. We discuss issues related to this special subgroup of patients.

Protecting the Endothelial Integrity of Internal Thoracic Arteries

BACKGROUND

Previous functional studies on human internal thoracic arteries, comparing the effect of the traditional harvesting method (occlusion with a clip) with a method leaving the artery perfused, revealed considerably impaired endothelial function associated with enhanced contractility after clipping. We have now investigated whether these observations could be correlated (1) with plasma markers of endothelial dysfunction, and (2) with structural changes in the endothelial layer.

METHODS

32 patients were randomly distributed into groups of clipped and perfused arteries. Arterial blood samples were obtained from both the artery and extracorporeal circulation to determine sP-selectin, sE-selectin, sL-selectin, and thrombomodulin using enzyme-linked immunosorbent assay. Arteries from three patients were examined by scanning electron microscopy.

RESULTS

Concentrations of sP-selectin and thrombomodulin were significantly higher in plasma from clipped arteries compared to perfused arteries, whereas sE-selectin and sL-selectin concentrations were similar within the groups. Scanning electron microscopy revealed significant structural changes and loss of endothelial cells in clipped arteries.

CONCLUSION

Biochemical and structural results support our findings that leaving the internal thoracic artery perfused preserves endothelial function in the arterial graft.

[Ambulatory long-term management of a left ventricular assist device. Current modality in terminal heart failure]

We report about the first use and successful outpatient therapy with an implantable pulsatile left ventricular assist device (LVAD, Novacor) in a patient with a combined dilative and ischemic cardiomyopathy in Switzerland. The patient, a 51 year old man (112 kg, 191 cm, blood type A) developed end-stage heart failure (New York Heart Association class (NYHA) IV) while he was awaiting orthotopic heart transplantation. Due to his profession as an independent graphic-designer the patient was afraid of a long-term temporary disablement with consecutive bankruptcy. Therefore we decided and performed the implantation of a Novacor-LVAD as a bridge to transplantation with the possibility to outpatient therapy in a favourable course. The patient was supported by the device for more than five months. His cardiac functional status returned to NYHA class I, and the patient was discharged 5 weeks after implantation. He returned into his normal life and started working at 100% again. Furthermore the LVAD enabled the patient to participate in almost all activities. Five months (151 days) after implantation a donor organ became available and the patient underwent orthotopic heart transplantation. The use and successful outpatient therapy with an implantable pulsatile left ventricular assist device in our patient has proved to be save, reliable, life-saving, quality of life improving and could be an important alternative for the economic burden in heart failure therapy.

Improved endothelial function after a modified harvesting technique of the internal thoracic artery

OBJECTIVE

One of the most important factors in bypass surgery is the preservation of endothelial function in the arterial graft. It was of interest, therefore, whether a slightly modified preparation procedure during surgery could contribute to improved endothelial function of the graft. We compared the functional activity of internal thoracic arteries (ITA) prepared according to the traditional harvesting method with occlusion by a clip, dissection at the distal end and storage of the artery in papaverine until its implantation (CA) with the functional activity of arteries which were also prepared and wrapped in papaverine, but were left perfused and dissected immediately before their anastomoses (PA).

METHODS

Samples of ITA were obtained from a total number of 28 patients, undergoing bypass surgery, and randomly distributed into two groups. The arteries were cut into rings and suspended in organ baths, containing Krebs-Henseleit solution, for isometric tension recording. Cumulative concentration response curves were determined for the contractile agents endothelin-1 (ET-1), 5-hydroxytryptamine (5-HT), noradrenaline (NA) and potassium chloride (KCl) and the relaxant compounds acetylcholine (ACH) and sodium nitroprusside (SNP) during active tone induced by 30 mM KCl.

RESULTS

ET-1 and 5-HT stimulated rings from both groups within the same concentration ranges but elicited significantly (P<0.05) higher contractile responses in CA compared to PA. By contrast, concentration response curves for KCl and NA where nearly superimposable. On the other hand, maximal endothelium-dependent relaxant responses to ACH proved to be significantly stronger in PA (0.84+/-0.20 g) as compared to CA (0.31+/-0.05 g, P<0.05) while endothelium independent relaxant responses to SNP where similar in both groups.

CONCLUSION

These data suggest that leaving the ITA perfused during harvesting might improve considerably the endothelial function of the graft.