Martin Hartrumpf

Is Bonewax Safe and Does It Help

BACKGROUND Bonewax is routinely used to seal sternal edges after median sternotomy. Adverse effects on sternal healing, however, have been proclaimed although clear evidence does not exist. We performed a study on coronary bypass patients with or without bonewax application to verify negative effects and risk factors for early rethoracotomy, wound healing problems, and mediastinitis. METHODS In a prospectively randomized study on 400 patients undergoing isolated coronary bypass surgery, 200 patients with (bonewax) and 200 patients without bonewax (nonwax) application after median sternotomy were compared. Blood product consumption, early rethoracotomy, sternum stabilization, mediastinitis, and early mortality were compared. Risk factors such as age, sex, diabetes mellitus, and bonewax were analyzed by means of logistical regression analysis. RESULTS Blood product consumption was almost identical in both groups (red blood cells, 3.9 +/- 4.7 units in the bonewax group; 3.8 +/- 3.4 units in the nonwax patients; fresh frozen plasma, 0.5 +/- 1.6 units versus 0.5 +/- 1.3 units; platelet concentrates, 0.07 +/- 0.3 units versus 0.04 +/- 0.2 units). Early rethoracotomy (bonewax 6.5%; nonwax 5%), sternal stabilization (bonewax 3%; nonwax 3%), and mediastinitis (bonewax 1%; nonwax 0.5%) did not differ significantly. Early mortality was 2.5% in the bonewax group and 0.5% in the nonwax cohort. Bonewax did not appear as an independent risk factor for adverse outcome. CONCLUSIONS Negative effects of bonewax on the percentage of postoperative complications and outcome were not shown. However, positive effects such as a reduction of blood product substitution were also not observed. Using bonewax on sternal edges is obviously safe but not particularly beneficial.

The use of Tachosil surgical patch or fibrin glue in coronary artery surgery does not affect quality of anastomosis or provoke postoperative adhesions in pigs.

OBJECTIVE Fibrin glue products and collagen surgical patches (TachoSil) coated with coagulation factors I and IIa are increasingly being used to prevent oozing from distal or proximal coronary anastomosis. Furthermore, an increasing number of patients are being operated upon anti-platelet therapy. These patients often exhibit diffuse bleeding. Especially in an off-pump scenario surgeons refrain from placing additional stitches in order to avoid an impairment of the graft. In these situations, a biological glue can help resolve this dilemma. It is, however, assumed that these products may exert negative effects on the anastomosis. For obvious reasons a systematic histological assessment in humans is impossible. Therefore, a chronic, large animal model was developed to study the fate of these products on a coronary anastomosis. METHODS In 15 pigs receiving off-pump coronary artery bypass graft of the left mammary artery to the left anterior descending coronary artery, three groups were defined. Group A served as control. In group B the anastomosis was covered with 1 ml fibrin glue; in group C TachoSil coverage was performed. Bypass flow (BF) was measured using a Doppler probe. After 3 months the pigs were sacrificed and the anastomoses were evaluated macroscopically and by means of light microscopy regarding patency and fibrosis. RESULTS In group A, all five animals survived, three of the five anastomoses were patent and the mean BF was 26 ml min(-1). In group B, three of the five animals survived, all anastomoses were patent. The BF was 21 ml min(-1). In group C, all five animals survived, four of the five anastomoses were patent and BF was 21 ml min(-1). Macroscopic and histological evaluation showed no differences between the groups. Remnants of Tachosil or fibrin glue were not observed. CONCLUSIONS In the chronic course, no evidence of adverse effects of TachoSil or fibrin glue was noted. Both agents can therefore be used safely in clinical practice for haemostyptic or positioning purposes.

Are mechanical valves with enhanced inner diameter advantageous in the small sized aortic annulus

BACKGROUND Mechanical bileaflet valves with enhanced inner diameter may offer superior hemodynamic properties in patients with a small aortic annulus. The aim of this clinical study was to compare these valves with standard bileaflet prostheses in vivo. METHODS Mechanical aortic valve replacement for combined stenosis and regurgitation was performed in 47 patients with standard CarboMedics prostheses (CM: 21 mm, 23 mm, 25 mm) and two types of diameter enhanced St. Jude Medical prostheses (SJM-AHPJ: 21 mm, 23 mm, 25 mm; SJM-Regent: 21 mm, 23 mm). Transvalvular mean gradients (TVG) were assessed intraoperatively by means of transesophageal echocardiography (TVG(TEE)) and simultaneous direct pressure monitoring of the left ventricle and the ascending aorta (TVG(CATH)), as well as early (3 months) and late (9 months) postoperatively by means of transthoracic echocardiography (TVG(TTE)). Left ventricular muscle mass was assessed preoperatively, early, and late postoperatively to evaluate remodeling capacity. RESULTS In all valve types and sizes, both TVG assessments exhibited consistent findings. Small-sized conventional valves of 21 mm showed a marked initial TVG. In contrast, both valve types with enhanced inner diameter exhibited significantly lower TVG comparable with those achieved with larger valves (TVG(CATH) CM 21 mm, 15.6 +/- 3.9 mm Hg; SJM-AHPJ 21 mm, 11.9 +/- 1.6 mm Hg; SJM-Regent 21 mm, 9.9 +/- 1.1 mm Hg; CM 23 mm, 7.8 +/- 0.8 mm Hg; SJM-AHPJ 23 mm, 7.7 +/- 1.4 mm Hg; SJM-Regent 23 mm, 9.5 +/- 1.8 mm Hg). During the postoperative course TVG remained constant in all valve types and sizes. Left ventricular muscle mass, however, diminished markedly in all valves without exhibiting significant differences between size matched valve types. CONCLUSIONS In patients with a small aortic annulus, who require a 21-mm valve, diameter-enhanced prostheses provide lower transvalvular gradients than conventional valves. However, in the intermediate clinical course, appropriate left ventricular remodeling occurred in all patients independent of the size and the type of the valve.

Surgeon performance index: tool for assessment of individual surgical quality in total quality management

BACKGROUND The surgeons individual performance is a key component of total quality management (TQM) in cardiac surgery. Early mortality as well as postoperative complications can be stratified in order to develop a surgeon performance index (SPI). MATERIAL AND METHODS In three consecutive annual periods (3703 patients) data of board-certified cardiac surgeons were compared. Risk-adjustment of early mortality and postoperative complications was performed by logistical EuroSCORE (logES). Early mortality (EM), early rethoracotomy for bleeding (ReTh), sternal rewiring for instability (ReWr), and mediastinitis (Med) were assessed. ReTh, ReWr, and Med were weighted according to empiric data: (ReThx2; ReWrx1; Medx3). Surgeon performance index was computed as follows: SPI=(EM/logES+[((ReTh/logES)x2)+((ReWr/logES)x1)+((Med/logES)x3)]/6)/2. Ideal SPI was considered <or=1. SPI of the respective previous period was handed out to each surgeon and discussed by means of a structured dialogue. RESULTS Patients from each period were allocated to 11 cardiac surgeons. Overall logES of the three periods were 6.6%, 9.1%, and 11.2% respectively; EM 5.7%, 6.6%, 5.6%; ReTh 5.8%, 7.3%, 10.9%; ReWr 2.4%, 1.9%, 1.4%; and Med 0.9%, 1.8%, 1.8%. SPI showed a mean of 0.71, 0.56, and 0.49. CONCLUSION Comorbidity increased between periods 1 and 3 significantly whereas early mortality remained rather stable. SPI indicated improvement of the performance of the individual surgeon and a decrease of range and mean of the overall performance. SPI is therefore an effective tool to assess individual surgical quality and serves as an instrument for human resource management and development. Sustainable positive effects on overall performance can be expected.

Infective endocarditis 4 months after transapical aortic valve implantation with Edwards SAPIEN™ XT

An 84-year old male had undergone an apical transapical aortic valve implantation. Subsequently, a reoperation for prosthetic endocarditis became necessary (Enterococcus durans). Intraoperatively, a massive destruction of the native annulus including abscess formation was found. We emphasize the risk of endocarditis in elderly TAVI patients in conjunction with possible unusual, pre-existing germs (Figs 1 and 2).

Hemodynamic Performance of Endovascular Valves as Valve-in-Valve in Small Stented Bioprosthesis

Background Endovascular valve in stented biological valve implantation (valve‐in‐valve transcatheter aortic valve implantation [TAVI ViV]) is increasingly becoming a valid option for bioprosthesis degeneration. TAVI implantation in small stented biological valves below 23 mm is controversially discussed. Reduced opening area and high gradients are typical objections against this procedure in cases of small bioprosthesis. Systematic studies about the hemodynamic performance of endovascular valves in small stented bioprosthesis, however, do not exist. Methods Stented biological valves of 21 mm size were analyzed in a pulse duplicator (cardiac output 4.9 L/min). Edwards Perimount Magna (EP; Edwards Lifesciences, Irvine, California, United States), Medtronic Mosaic (MM; Medtronic Inc., Minneapolis, Minnesota, United States), and Sorin Mitroflow (SM; Milan, Italy) were investigated (three valves, each type). Mean transvalvular gradients were measured before and after implantation of Edwards Sapien 23 mm (SAP) as ViV. Results There were no marked differences of mean transvalvular gradients before and after ViV (EP21: 12.3 mm Hg; EP21 + SAP: 11.1 mm Hg; SM21: 13.5 mm Hg; SM21 + SAP: 14.9 mm Hg; MM21: 21.4 mm Hg; MM21 + SAP: 15.1 mm Hg). MM valves fabricated from porcine cusps showed higher initial gradients in contrast to valves constructed with pericardium (EP and SM). After ViV, however, this difference was reduced. Conclusion This in vitro study shows that hemodynamic performance of endovascular valves as ViV in small bioprosthesis does not differ significantly from the performance of the initial implanted prosthesis. Hemodynamic performance of porcine cusp valves could even be optimized. It can thus be speculated that TAVI ViV also offers a reasonable option for patients with typical stented bioprosthetic degeneration to substantially prolong adequate function with one initial surgical and one consecutive interventional procedure even in small valves.

Radiation Exposure and Contrast Volume Differ between Transapical and Transfemoral Aortic Valve Implantation with the Edwards SAPIEN Aortic Valve

BACKGROUND To date, little is known about the radiation exposure and the amount of contrast medium given during the transcatheter aortic valve implantation (TAVI) procedure. This study compares our data between the transfemoral (TF) approach and the transapical (TA) approach. PATIENTS AND METHODS A total of 216 TA and 180 TF implantations of the Edwards SAPIEN (Edwards Lifesciences, Irvine, California, United States) valve were consecutively performed by our heart team, consisting of cardiac surgeons and cardiologists. Fluoroscopy time, dose area product, and contrast volume were compared between both the approaches. RESULTS TF-TAVI showed higher values of fluoroscopy time (13.1 ± 5.9 vs. 7.0 ± 5.7 minutes, p < 0.001), dose area product (5.0 ± 3.9 vs. 2.7 ± 1.9 mGy·m(2), p < 0.001), and contrast volume (196.7 ± 72.7 vs. 109.2 ± 33.8 mL, p < 0.001). All physicians performing the TF approach exceeded the mean values of the surgeons performing the TA approach. Some physicians showed a trend toward lower values with growing experience. Vascular complications and postdilatation had only a minor impact on the study parameters. CONCLUSION TA-TAVI showed an advantage over TF-TAVI in terms of lower fluoroscopy time, dose area product, and contrast use. This was hardly reflected in the past and should be considered when comparing invasiveness of both methods. However, human factors also play a role as most physicians showed a learning curve toward lower values over time.

Suboptimal geometrical implantation of biological aortic valves provokes functional deficits

Endovascular valves have become a valid option for patients not qualifying for conventional surgery. Biological valves mounted in a stent are currently used. After implantation, however, geometrical distortion of the valve can occur. We tested whether biological valves suitable for transcatheter implantation exhibit hemodynamic deficits after deployment in a distorted position. Two types of valves [bovine pericardium (BP) and porcine cusps], of 21 and 23 mm diameter, respectively were investigated. Mean transvalvular gradient (TVG), effective orifice area (EOA), and regurgitation fraction (REG) were measured prior to and after the 20% distortion of the original diameter. All valves exhibited an increase of TVG and reduction of EOA whereas REG increased only in BP valves after distortion. The 21 mm valves demonstrated a more pronounced alteration than the 23 mm valves. Even moderately distorted implantation of a biological valve results in a marked functional alteration. The susceptibility of pericardial valves is higher than that of porcine valves probably owing to better coaptation properties of native cusps even under deformed conditions when compared to valves constructed with pericardium. Care should therefore be taken during implantation of endovascular valves in order to avoid fixed hemodynamic deficits. Native valves may preferably be used as they demonstrate a more robust behavior regarding suboptimal implantation.

How Do Transcatheter Heart Valves Fit in Mitral Annuloplasty Rings and Which Combination Can be Recommended

BACKGROUND  Transcatheter heart valve (THV) as valve-in-ring is increasingly used in the mitral position. Semi-rigid rings may serve as a more appropriate scaffold for proper anchoring of a THV as they may change from their oval to a round shape thereby fitting to the implanted THV. METHODS  One rigid and five semi-rigid rings of four manufacturers, Edwards Physio I and II, Sorin 3D Memo, Medtronic Simulus, and St. Jude Medical (SJM) Saddle and SJM Sequin, with sizes 28 to 36 mm and Edwards Sapien III THV 23, 26, and 29 mm were used. Preevaluation comprised insertion/inflation of the THV into the ring and visual inspection for the paravalvular gap ≥ 4 mm2. Only valves not showing paravalvular gap were then submitted to hemodynamic evaluation with a pulse duplicator. Cusp movement was assessed with a high-speed-camera. Mean transvalvular gradients (TVGs) were measured. RESULTS  SJM Saddle ring of all sizes and SJM Sequin ring 34 showed marked gaps combined with all THV sizes, thus not undergoing hemodynamic testing. It was further shown that ring sizes ≥ 36 mm did not allow for a proper fit of even the largest THV into the ring of all the manufacturers and were consequently not hemodynamically evaluated. The 23 mm THV was too small for any ring size. The lowest gradients were achieved with the 26 mm THV in 30 and 32 mm and the 29 mm THV in 32 and 34 mm rings. CONCLUSION  Not all currently available annuloplasty rings are ideal scaffolds for THV placement. It appears that a more proper fit can be achieved with semi-rigid rings than with rigid ones. Note that 23 mm THV appeared to be too small for an adequate anchoring in even the smallest available ring. Thus, 26 mm as well as 29 mm THV fit properly in ring sizes between 28 and 34 mm. Surgeons may consider to choose from those ring brands and sizes which allow for good placement of a THV in view of possible valve degeneration in the later course.

Double-Wire versus Single-Wire Sternal Closure in Obese Patients: a Randomized Prospective Study

Background Sternal instability after coronary artery bypass grafting (CABG) is a serious complication. Obese patients are at high risk for sternal instability after CABG. This study was conducted to assess the positive impact of double‐wire sternal closure on sternal instability. Methods A total of 200 obese patients with a body mass index ≥ 30 kg/m2 undergoing isolated CABG with left internal mammary artery (LIMA) graft were randomly assigned to sternal closure either by eight single wires (n = 100) or by a combination of four double wires and four single wires. Results There was a total of 21 cases with sternal instability: 5 cases (i.e., 5%) in the double‐wire group versus 16 cases (16%) in the single‐wire group (p = 0.019). Logistic regression analysis showed sternal closure via double wires as an independent protection factor (odds ratio [OR]: 0.276; p = 0.029). Smoking (OR: 5.5; p = 0.006) and postoperative delirium (OR: 3.5; p = 0.033) turned out to be independent risk factors for the development of sternal instability. Conclusion Double‐wire sternal closure significantly reduces postoperative sternal instability in obese patients undergoing isolated CABG with LIMA graft.