Kirk Graves

Fibroblast activation protein is induced by inflammation and degrades type I collagen in thin-cap fibroatheromata

Aims Collagen degradation in atherosclerotic plaques with thin fibrous caps renders them more prone to rupture. Fibroblast activation protein (FAP) plays a role in arthritis and tumour formation through its collagenase activity. However, the significance of FAP in thin-cap human fibroatheromata remains unknown. Methods and results We detected enhanced FAP expression in type IV–V human aortic atheromata (n = 12), compared with type II–III lesions (n = 9; P < 0.01) and healthy aortae (n = 8; P < 0.01) by immunostaining and western blot analyses. Fibroblast activation protein was also increased in thin-cap (<65 µm) vs. thick-cap (≥65 µm) human coronary fibroatheromata (n = 12; P < 0.01). Fibroblast activation protein was expressed by human aortic smooth muscle cells (HASMC) as shown by colocalization on immunofluorescent aortic plaque stainings (n = 10; P < 0.01) and by flow cytometry in cell culture. Although macrophages did not express FAP, macrophage burden in human aortic plaques correlated with FAP expression (n = 12; R2= 0.763; P < 0.05). Enzyme-linked immunosorbent assays showed a time- and dose-dependent up-regulation of FAP in response to human tumour necrosis factor α (TNFα) in HASMC (n = 6; P < 0.01). Moreover, supernatants from peripheral blood-derived macrophages induced FAP expression in cultured HASMC (n = 6; P < 0.01), an effect abolished by blocking TNFα (n = 6; P < 0.01). Fibroblast activation protein associated with collagen-poor regions in human coronary fibrous caps and digested type I collagen and gelatin in vitro (n = 6; P < 0.01). Zymography revealed that FAP-mediated collagenase activity was neutralized by an antibody directed against the FAP catalytic domain both in HASMC (n = 6; P < 0.01) and in fibrous caps of atherosclerotic plaques (n = 10; P < 0.01). Conclusion Fibroblast activation protein expression in HASMC is induced by macrophage-derived TNFα. Fibroblast activation protein associates with thin-cap human coronary fibroatheromata and contributes to type I collagen breakdown in fibrous caps.

Gold-coated pacemaker implantation after allergic reactions to pacemaker compounds

An 86-year-old man underwent pacemaker implantation for symptomatic atrio-ventricular block grade 2 Mobitz II. The patient suffered repeated admissions for iterative sterile wound necrosis, leading to two generator re-implantations. No bacterial infection was detected in the microbiological screening tests. The skin patch testing to titanium was negative. Nevertheless, we decided to remove the pacemaker system and to implant a gold-plated generator with polyurethane leads. Since then, there has been no recurrence of wound complications. Gold-plated generator and polyurethane leads are effective in treating allergic reactions to pacemaker system components in selected cases. Negative skin patch testing to titanium does not exclude allergic reaction to this pacemaker component.

Monitoring activated clotting time for combined heparin and aprotinin application : An in vitro evaluation of a new aprotinin-insensitive test using SONOCLOT

The kaolin-based activated clotting time (ACT) is commonly used for monitoring heparin-induced anticoagulation alone and combined with aprotinin during cardiopulmonary bypass. However, aprotinin prolongs ACT measurements. Recently, a new so-called ‘aprotinin-insensitive‘ ACT test (SaiACT) has been developed for the SONOCLOT analyzer. In this study we evaluated and compared this new test for the SONOCLOT analyzer in vitro with an established kaolin-based ACT from HEMOCHRON (HkACT). Twenty-five patients undergoing elective valve surgery donated 80 mL of blood after induction of anesthesia. The blood was withdrawn in citrated tubes and processed to analyze effects of heparin (0, 1, 2, and 3 U · mL−1), aprotinin (0, 200 kIU · mL−1), and 25% hemodilution with calcium-free lactated Ringer’s solution on ACT measurements. A total of 400 blood samples were analyzed and ACT was measured in a wide, clinically relevant range in duplicate with SaiACT and HkACT. Addition of aprotinin to heparinized blood samples induced no significant changes of SaiACT measurements. By contrast, HkACT readings increased significantly: aprotinin prolonged HkACT in heparinized blood samples by 20% ± 37% (2 U · mL−1) and 24% ± 18% (3 U · mL−1), respectively, and in vitro hemodilution increased this effect.

Fatal disconnection of a ventricular assist device in an out-of-hospital setting

The case of a 63-year-old Caucasian male suffering from secondary dilatative cardiomyopathy due to ischaemic and consecutive valvular heart disease was reported. He had had bypass surgery and mitral valve replacement in 2002 after mitral chord rupture. Five years later, several episodes of arrhythmias occurred (recurrent atrial fibrillation and ventricular tachycardia) and his cardiac function decreased. Echocardiographic examination revealed an ejection fraction of 25% and, subsequently, he was listed for cardiac transplantation. Despite extensive conservative treatment, the patient developed end-stage heart failure and a biventricular ventricular assist device (VAD) (EXCOR VAD ®, Berlin Heart AG, Berlin, Germany, figure 1) was implanted at the end of 2007. The patient recovered from this operation without any complications and was discharged home after receiving specific instruction for VAD management. Regular assessments and controls were performed at the hospital on an outpatient basis. Figure 1 Diagram of a biventricular ventricular assist device (VAD) (EXCOR VAD ®, Berlin Heart AG, Berlin, Germany). AC, air chamber; …

Oxidized regenerated cellulose in cardiac computer tomography imaging

Oxidized regenerated cellulose is widely used as a bioabsorbable topical hemostatic agent. Postoperative visualization of this material through routine chest imaging, such as conventional radiography, computer tomography (CT), magnetic resonance imaging as well as sonography, may prove difficult and, to our knowledge, is not described in the literature. We describe a case where the mediastinal packing with Surgicel™ Nu-Knit™ after a mitral valve repair procedure led to a delayed obstruction of the superior vena cava, necessitating a re-thoracotomy and curettage of the hemostatic material. The hemostatic agent was not prospectively interpreted as the cause of a severe upper inflow restriction, despite repeated imaging. Retrospectively, the hemostatic material as a cause of the upper inflow obstruction could have been identified earlier if its presence would have been known to the radiologist. We strongly recommend that the surgeon inform the radiologist that such materials were used to improve the diagnostic yield of CT interpretation.

Evaluation of a New Sonoclot Device for Heparin Management in Cardiac Surgery

Background: Sonoclot is used to measure kaolin-based activated clotting time (kACT) for heparin management. Apart from measuring kACT, the device assesses the patient’s coagulation status by glass bead–activated tests (gbACTs; measuring also clot rate [CR] and platelet function [PF]). Recently, a new version of the Sonoclot has been released, and the redesign may result in performance changes. The aim of this study was to evaluate and compare the performance of the new (S2) and the previous (S1) Sonoclot. Methods: The S1 was used in the routine management of 30 patients undergoing elective cardiac surgery. Blood samples were taken at baseline (T1), after heparin administration (200 U/kg, 100 U/kg; T2 and T3), during cardiopulmonary bypass (T4), after protamine infusion (T5), and before intensive care unit transfer (T6). Kaolin-based activated clotting time and gbACTs were measured in duplicate by both the old and the new device and performance compared by Bland-Altman analysis and percentage error calculation. Results: A total of 300 kACT and 180 gbACTs were available. Bland-Altman analysis for kACT revealed that S2 consistently reported results in shorter time compared to S1 (overall = −14.7%). Comparing S2 and S1, the glass bead–activated tests showed mean percentage differences of −18.9% (gbACTs), +37.4% (CR), and −3.7% (PF). Conclusion: Since clotting is faster in the new S2 compared to S1, shorter clotting times have to be considered in clinical practice. The use of S2 kACT in heparin management will result in higher heparin and protamine dosing unless heparin kACT target values are adjusted to correct for the differences in results between S1 and S2.

Avoidance of aortic side-clamping for proximal bypass anastomoses: better short-term outcome?

OBJECTIVES The benefit of off-pump coronary artery bypass (OPCAB) surgery may be reduced by strokes caused by microemboli produced after aortic side-clamping for proximal bypass anastomoses. The Heartstring device allows constructing proximal bypass anastomoses without side-clamping of the aorta. METHODS This retrospective study describes 260 consecutive patients who underwent OPCAB surgery; 442 proximal anastomoses were performed with the Heartstring device in this series. Ten percent of the patients were randomly sampled before discharge to undergo a coronary angiogram for assessment of graft patency. RESULTS Intraoperative Doppler measurements confirmed regular bypass function. Early mortality occurred in 4 patients (1.5%), and stroke occurred in 2 patients (0.8%). Device-related bleeding was negligible, and there were no cases of aortic dissection. Perioperative ischemia occurred in 8 patients (3.1%). Predischarge coronary angiography evaluations in 25 of the patients (of 260) showed that all 42 Heartstring-assisted anastomoses (of 442) were patent. CONCLUSIONS Clampless performance of proximal bypass anastomoses combined with OPCAB is associated with a very low incidence of stroke complications. Short-term follow-up has shown excellent results regarding bypass patency and other adverse events. Prospective randomized trials are required to confirm the advantage of this technique.

Aortic posterior wall perforation with automatic aortic cutter during routine off-pump coronary bypass grafting

Aortic complications are very rare during off-pump coronary artery bypass grafting (OPCAB). When they occur, the mortality is high. We report a case of perforation of the posterior aortic wall after punching out the hole in the ascending aorta with an automatic aortic cutter to avoid clamping for the proximal anastomosis during a routine OPCAB procedure. The consequence was a massive hemorrhage, emergency conversion to cardiopulmonary bypass and replacement of the aortic valve and of the ascending aorta.

Fast-Track Management in Off-Pump Coronary Artery Bypass Grafting: Dexmedetomidine Provides Rapid Extubation and Effective Pain Modulation

BACKGROUND  Dexmedetomidine (DEX) is a highly selective α-2 agonist with many desirable effects including analgesia, improvement of hemodynamic stability, and potential myocardial and renal protection. The aim of this study was to investigate the effect of DEX on patients undergoing off-pump coronary artery bypass (OPCAB) grafting with regard to less pain medication, earlier extubation, faster transfer to normal ward, and cardiac protection. PATIENTS AND METHODS  From January 2012 to March 2015, 464 patients receiving OPCAB were included for retrospective analysis. After propensity matching (1:1), two groups (DEX vs. propofol, n = 129) could be compared. Continuous and categorical variables were reported as mean ± standard deviation or percentages, and compared with the chi-square test and the Mann-Whitneys test, respectively. RESULTS  In the DEX group, less use of pain medication in the initial phase at intensive care unit was observed. During the first 2 hours, DEX patients received more nicomorphine (DEX 8 ± 3.2 mg vs. propofol 6 ± 4 mg, p < 0.001), while in the following 2 hours, the pain medication was significantly reduced (DEX 3.2 ± 2.8 mg vs. propofol 4.7 ± 3.3 mg, p < 0.001). Remifentanil was stopped considerably earlier (DEX 238 ± 209 minutes vs. propofol 353 ± 266 minutes, p < 0.001). DEX led to earlier extubation (DEX 208 ± 106 minutes vs. propofol 307 ± 230 minutes, p < 0.001) and less postoperative atrial fibrillation (AF) (p = 0.01). CONCLUSION  Early postoperative DEX application supports the fast-track strategy in patients after OPCAB through enabling rapid extubation, effective pain control, and reduced occurrence of new-onset AF. We are confident to give precedence to DEX over propofol as the new routine medication during postoperative patient transfer.

Tricuspid Valve Repair for the Poor Right Ventricle: Tricuspid Valve Repair in Patients with Mild-to-Moderate Tricuspid Regurgitation Undergoing Mitral Valve Repair Improves In-Hospital Outcome.

Background Tricuspid regurgitation (TR) in patients undergoing surgery for mitral valve (MV) increases morbidity and mortality, especially in case of a poor right ventricle. Does repair of mild‐to‐moderate insufficiency of the tricuspid valve (TV) in patients undergoing MV surgery lead to a benefit in early postoperative outcome? Methods A total of 22 patients with mild‐to‐moderate TR underwent MV repair and concomitant TV repair with Tri‐Ad (Medtronic ATS Medical Inc., Minneapolis, Minnesota, United States) and Edwards Cosgrove (Edwards Lifesciences Irvine, California, United States) rings. The severity of TR was assessed echocardiographically by using color‐Doppler flow images. The tricuspid annular plane systolic excursion (TAPSE) was under 1.7 cm. Additional procedures included coronary artery bypass (n = 9) and maze procedure (n = 15). The following parameters were compared: postoperative and peak dose of noradrenaline (NA), pre/postoperative systolic pulmonary pressure (sPAP), extubation time, operation time, cross‐clamp time, cardiopulmonary bypass (CPB) time, pre/postoperative ejection fraction (EF), intensive care unit (ICU)‐stay, hospital stay, cell saver blood transfusion, intra/postoperative blood transfusion, and postoperative TR. Results The mean age was 67 ± 14.8 years, 45% were male. Mean EF was 47 ± 16.2%, postoperative 52 ± 12.4%. sPAP was 46 ± 20.1 mm Hg preoperatively, sPAP was 40.6 ± 9.4 mm Hg postoperatively, NA postoperatively was 12 ± 10 &mgr;g/min, NA peak was 18 ± 11 &mgr;g/min, operation time was 275 ± 92 minutes, CPB was 145 ± 49 minutes, ICU stay was 2.4 ± 2.4 days, hospital stay was 10.8 ± 3.5 days, cell saver blood transfusion was 736 ± 346 mL, intraoperative transfusions were 2.5 ± 1.6. Two patients needed postoperative transfusions. A total of 19 patients were extubated at the 1st postoperative day, 2 patients at the 2nd day, and 1 at the 4th postoperative day. Two patients required a pacemaker. No reintubation, no in‐hospital mortality, and one reoperation because of bleeding complications. Conclusion Correction of mild‐to‐moderate TR at the time of MV repair does maintain TV function and avoid right ventricular dysfunction in the early postoperative period improving the clinical outcome.