Delayed two-step free wall rupture of the right and left ventricular wall after myocardial infarction.

We present a 68-year-old female who suffered extensive complications after severe myocardial infarction (MI) in the circumflex (CX) territory. At 24 hours after the initial event, the patient presented with a covered right ventricular free wall rupture (FWR) which was followed by a rupture of the left posterior wall ten days later. We report here on a rare case of delayed two-step biventricular FWR after severe MI in the CX territory.

Sternal plate closure: indications, surgical procedure and follow-up.

OBJECTIVES: Titanium plate osteosynthesis (Synthes) is an alternative option for sternal closure. The indications and time point of application are still debated. This study investigated the application and feasibility of this technique after median sternotomy. METHODS: Forty-one patients (29 M/12F, mean age 63 ± 17 years) received the plate system for complicated sternal conditions. Indications, intraoperative course and postoperative follow-up were assessed. RESULTS: Sternal deformity was present in 5 % (2/41), sternal fractures in 17 % (7/41), bone defect in 12 % (5/41), wire loosening in 39 % (16/41) and pseudoarthrosis in 27 % (11/41). 54 % (22/41) of patients showed concomitant sternal infection. Two intraoperative complications were noted: mammary artery injury (1 patient), pleural injury (1 patient). At discharge the patients reported no pain (90 %, 37/41) or only occasional discomfort (10 %, 4/41). Postoperative complications were subcutaneous hematoma in 12 % (5/41), seroma in 12 % (5/41) and sternal reinfection in 7 % (3/41). 12 % (5/41) showed occasional discomfort and 7 % (3/41) had persistent pain leading to plate removal. CONCLUSION: The Titanium Sternal Fixation System is comfortable and easy to use. It can be used to treat a wide spectrum of indications, especially for pseudoarthrosis, an entity which has not yet received sufficient attention.

Spacecraft bacterium, Paenibacillus pasadenensis, causing wound infection in humans.

In a patient with mediastinitis after cardiac surgery Paenibacillus pasadenensis was detected in his sternal wound. Paenibacilli are gram-positive, aerobic, bacteria related to bacilli. Until recently these organisms were not known to cause human disease. A few cases of human infection caused by another member of this genus, P alvei, have been reported. The authors describe the first infection with P pasadenensis in humans. P pasadenensis was detected by broad-range bacterial 16S rRNA PCR. Treatment consisted of surgical debridement and antibiotics, vancomycin and ciprofloxacin followed by clindamycin and ciprofloxacin, resulting in complete recovery.

Off-pump coronary artery bypass grafting: the Zurich experience.

Coronary artery bypass grafting (CABG) is the surgical procedure of choice for treatment of multi-vessel coronary artery disease. The rising risk profile of the patients requiring isolated CABG and the economic pressure have prompted us to devise new operative strategies to treat these patients. Elimination of the cardiopulmonary bypass is one possible answer to the dilemma of maintaining the quality of care and reducing the exploding costs of our health system. Therefore, we developed the off-pump coronary artery bypass grafting (OPCAB) for patients requiring isolated CABG. In our experience the key to successful OPCAB relies on the order of revascularization of the myocardial walls (anterior, inferior, lateral), use of intracoronary shunt, no-touch technique for the proximal aortic anastomosis with heart string â (Guidant, IN, USA), close collaboration with the anesthesiologists, early and aggressive administration of anti-platelet therapy, endoscopic vein harvest by perfusionists, and improved body temperature control. Following these concepts, we have been able to offer the OPCAB procedure to over 90% of our patients and to reduce perioperative morbidity and global costs.

Cystic tumor in the left atrium: an unusual aspect of a myxoma.

Most cardiac tumors are benign, whereas up to 50 % of the diagnosed cases are histologically myxomas. The common clinical signs are rhythm disturbances, myocardial ischemia, pulmonary edema, syncope and cardiac arrest. They do normally lead to the diagnostic hypothesis of an intracardiac mass. The primary modality for imaging is echocardiography which usually confirms the suspected diagnosis. But in rare cases there are masses which cannot be exactly identified by this technique. Here we present a patient with an atypical echocardiography of an unusual intracardiac tumor.

Continuous blood pressure monitoring utilizing a CMOS tactile sensor.

A novel tactile device based on a monolithically integrated sensor chip is presented for external blood pressure measurement. It uses a tonometric principle, thus allowing for continuous monitoring of the blood pressure without the need for an invasive catheter. On the chip, the deflection of membranes in an array is sensed capacitively and read out using a SigmaDelta-modulator. The membrane array and the modulator are fabricated on a single chip using an industrial CMOS (complementary metal oxide semiconductor) technology combined with post-process micromachining to achieve small and portable devices with low power consumption. The tested device is operated at a conversion rate of 1 kilosamples per second and is pressure biased to a 2000 hPa (1500 mmHg) reference point. The power consumption of the sensor chip is 11.5 mW with signal-to-noise ratio better than 72 dB. During testing a pressure resolution of approximately 8 hPa (6 mmHg) for one digit at the output of the SigmaDelta-modulator is achieved over the range of interest continuous blood pressure monitoring using this CMOS-based tactile device is successfully demonstrated. The characteristic features of a blood pressure waveform are clearly recognizable from the acquired data.

Experiences in robotically enhanced IMA-preparation as initial step towards totally endoscopic coronary artery bypass grafting.

AIM: To evaluate the feasibility of robotically enhanced preparation of internal mammary arteries (IMA). METHOD: Via three trocars in left thoracic wall the left, right or both IMA were skeletonized under CO(2) insufflation and single lung ventilation using electrocautery. RESULTS: In 12 months, 26 LIMA, five BIMA and one RIMA were dissected. In five patients, the procedure had to be determined (IMA injury (two), respiratory insufficiency (two), and heart penetration (one)). Mean intrathoracic pressure was 9.7+/-1.5 mmHg. Mean time for LIMA and RIMA dissection was 66.7+/-21.1 and 99.2+/-8.7 min, respectively. In 10 patients, pericardium was incised and course of LAD assessed. However, in two patients, this coronary did not correlate with LAD. Time for instrument change depended on type of tool (cautery blade: 24.9+/-13.1 s, clip applier 72.8+/-28.4 s). CONCLUSION: Robotic dissection of IMA is reasonable. However, life-threatening complications can barely be managed due to inadequate tools and excessive time for instrument change. Incorrect determination of coronaries can result in misplaced anastomoses.

Regulation of matrix metalloproteinases and effect of MMP-inhibition in heart transplant related reperfusion injury.

PURPOSE: Metalloproteinases (MMPs) regulate extracellular matrix turnover and degrade basal lamina. Aim of the study was to examine the regulation of MMPs and the effect of an MMP inhibitor in transplant related ischemia/reperfusion injury. METHODS: Heterotopic cardiac transplantation was performed after 4 h of ischemia in three groups of six rats: allografts (black hooded inbred strain, PVG donor/August Copenhagen Irish inbred strain recipient); allografts treated with a competitive MMP-inhibitor (Batimastat) 15 mg/kg every 24 h; isografts (PVG donor and recipient). Normal PVG hearts served as a control. Hearts were explanted after 72 h of reperfusion. Expression of MMP-2 and -9 was measured using gelatin zymography. Proteolytic activity was measured using a gelatinase activity assay. Myeloperoxidase activity and tumor necrosis factor-alpha (TNF-alpha) were measured as markers of inflammatory response. Immunostaining for collagen IV and laminin was used to study degradation of basal lamina. RESULTS: There was a significant increase of MMP-2 expression in allografts (2271+/-571 microg/ml) as compared to normal (683+/-139 microg/ml) and the Batimastat-treated (259+/-140 microg/ml, P<0.05) groups. Although pro-MMP-2 expression was equally high in the untreated iso- and allograft group (75+/-23 versus 62+/-30 microg/ml) MMP-2 expression in the isograft hearts was significantly lower (359+/-267 microg/ml) suggesting activation of the pro-form by an immunologic mechanism. Pro-MMP-9 levels were significantly higher in the untreated iso- and allograft groups as opposed to normal hearts and MMP-inhibited hearts. MMP-9 was completely inhibited by Batimastat treatment. Collagenolytic activity was lower in the treated group as compared to untreated allografts (538+/-140 versus 384+/-97 microg/ml, P<0.05), demonstrating effective inhibition of MMPs by Batimastat. In the treated group a lesser extent of basement membrane component alterations could be demonstrated by laminin and collagen IV staining. There was a significant reduction in myeloperoxidase activity (P=0.027) as well as lower TNF-alpha levels (ns) in the in the Batimastat treated group. CONCLUSION: Ischemia leads to an increase in MMP expression and degradation of basal lamina. This process is enhanced in allografts as compared to isografts suggesting additional activation of MMPs by immunologic mechanisms. MMP-inhibition is effective in preventing the proteolytic activity of MMPs and may alter the host rejection response by preserving extracellular matrix components and basement membranes.

Influence of three-dimensional vision on surgical telemanipulator performance.

BACKGROUND: Different viewing conditions (two- and three-dimensional National Television Standard Committee [2D-NTSC and 3D-NTSC] and two-dimensional high-definition television [2D-HDTV]) on telemanipulator performance were evaluated. METHODS: Six taskes were performed by 15 endoscopic surgeons using the daVinci telemanipulation system. Performance time and errors were measured. Encoder data from the system were used for kinematic analysis of motion. A self-evaluation questionnaire regarding performance under various viewing conditions was obtained. RESULTS: Resolution was better with 2D-HDTV. The estimate of relative distance was not influenced by the different visualization systems. Motor skill tasks were performed faster with binocular vision (3D-NTSC) than with monocular vision (2D-NTSC, 2D-HDTV). For both 2D settings, the deceleration phase of motion was prolonged (p < 0.05 vs 3D). Peak velocity was reduced with 2D-HDTV as compared with 3D-NTSC (p = 0.01). The surgeons tended to favor the 3D system despite their use of 2D systems in their own practice. CONCLUSIONS: Three-dimensional vision enhances telemanipulator performance as compared with a 2D system at the same or higher level of resolution. Because it allows faster and more precise movement, future surgical systems should focus on 3D visualization.

Preoperative administration of steroids: influence on adhesion molecules and cytokines after cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with tissue damage mediated by adhesion molecules and cytokines. Prebypass steroid administration may modulate the inflammatory response, resulting in improved postoperative recovery. METHODS: Fifty patients undergoing elective coronary operations under normothermic CPB were randomized into two groups: group A (n = 24) received intravenous methylprednisolone (10 mg/kg) 4 hours preoperatively, and group B (n = 26) served as controls. Cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin-2R [IL-2R], IL-6, IL-8), soluble adhesion molecules (sE-selectin, sICAM-1), C-reactive protein, and leukocytes were measured before steroid application, then 24 and 48 hours, and 6 days postoperatively. Adhesion molecules were measured by enzyme-linked immunosorbent assay, cytokines by chemiluminescent immunoassay. Postoperatively, hemodynamic measurements, inotropic agent requirements, blood loss, duration of mechanical ventilation, and intensive care unit stay were compared. RESULTS: Aortic cross-clamp and CPB time was similar in both groups. Prednisolone administration reduced postoperative levels of IL-6 (611 versus 92.7 pg/mL; p = 0.003), TNF-alpha (24.4 versus 11.0 pg/L, p = 0.02), and E-selectin (327 versus 107 ng/mL, p = 0.02). Postoperative recovery did not differ between groups. CONCLUSIONS: Preoperative administration of methylprednisolone blunted the increase of IL-6, TNF-alpha, and E-selectin levels after CPB but had no measurable effect on postoperative recovery.

Upregulation of Bcl-2 through caspase-3 inhibition ameliorates ischemia/reperfusion injury in rat cardiac allografts.

BACKGROUND: Oxidative stress after ischemia/reperfusion of cardiac allografts leads to cytokine production. Bcl-2, an inhibitor of apoptosis, also has strong antioxidant properties. Caspase-3 is known to cleave bcl-2. This study tests the hypothesis that bcl-2 is downregulated while tumor necrosis factor-alpha (TNF-alpha) levels increase after cardiac transplantation. Furthermore, the use of caspase-3 inhibition was investigated as a strategy for preserving myocardial bcl-2 and mitochondrial cytochrome c after transplantation. METHODS AND RESULTS: PVG-to-ACI rat heterotopic cardiac transplantations were performed in 4 groups designed with 30 minutes' ischemia and 4 or 8 hours of reperfusion (n=4 per group). Treatment consisted of DEVD-CHO 500 microgram IP per animal to donor and recipient 2 hours before transplantation and 250 microgram IC into allograft. Controls were treated with saline. Grafts were analyzed by reverse transcription-polymerase chain reaction for bcl-2 mRNA, by ELISA for TNF-alpha, for myeloperoxidase activity, and by Western blot for cytochrome c. In untreated groups, bcl-2 mRNA decreased significantly over time, whereas TNF-alpha increased significantly at 4 hours (P=0.003) and returned to baseline after 8 hours' reperfusion (P=NS compared with normal hearts). Treatment with caspase-3 inhibitor showed significant upregulation of bcl-2 mRNA expression after 4 and 8 hours of reperfusion (P<0.001 versus control), with a concomitant decrease in TNF-alpha to baseline levels. Myeloperoxidase activity in all groups was no different from that of normal hearts. Mitochondrial cytochrome c release increased in both control and treatment groups. CONCLUSIONS: Bcl-2 is actively downregulated and TNF-alpha is upregulated in this model of cardiac allograft ischemia/reperfusion. Furthermore, the caspase-3 pathway is linked to this process, and blockade of caspase-3 can ameliorate reperfusion injury by upregulating bcl-2 and inhibiting TNF-alpha without affecting cytochrome c release.

Genetic predisposition in patients undergoing cardiopulmonary bypass surgery is associated with an increase of inflammatory cytokines.

OBJECTIVE: Cardiopulmonary bypass (CPB) surgery induces a transient rise in pro-inflammatory cytokines typically released by activated monocytes. The E4 variant of apolipoprotein E is a recognized risk factor for atherosclerosis. It has recently been shown that apolipoprotein E affects monocyte functions in vitro and leads to higher levels of median lipoprotein (a) in humans. The aim of the study is to investigate if the E4 genetic variant of apolipoprotein E affects cytokine release after CPB surgery. METHODS: 22 patients were operated on with standard coronary artery bypass grafting. Concentrations of interleukin 8 (IL-8) and tumor necrosis factor (TNF-alpha) were measured by automated Immulite immunoassay at regular intervals within 48 h after surgery. Total apparent cytokine outputs were calculated as area under the curve. Results are expressed as mean+/-standard deviation and compared by unpaired t-test. RESULTS: In the presented patient population 6 (27%) carried the E4 allele. Sixteen (63%) showed no E4 allele. Mean cross clamp time (CCT) was 56.2+/-13.5 min versus 55.7+/-12.1 min and CPB time was 91.8+/-17.5 versus 93.5+/-15.7 min. No statistical difference between E4-carriers and E4 non-carriers regarding CCT and CPB was observed. The total amount of IL-8 and TNF-alpha was higher in patients carrying the E4 genetic variant of apolipoprotein E in comparison to E4 non-carriers (P<0.08, P<0.039). CONCLUSION: The presence of the E4 allele is associated with increased release of IL-8 and TNF-alpha after CBP surgery. The preoperative determination of E4 in patients undergoing cardiac surgery may lead to additional perioperative measures for the treatment of an increased systemic inflammatory response.

Optimal cell source for cardiovascular tissue engineering: venous vs. aortic human myofibroblasts.

Arterial vascular cells have been successfully utilized for tissue engineering in human cardiovascular structures, such as heart valves. The present study evaluates saphenous vein-derived myofibroblasts as an alternative, easy-to-access cell source for human cardiovascular tissue engineering. Biodegradable polyurethane scaffolds were seeded with human vascular myofibroblasts. Group A consisted of scaffolds seeded with cells from ascending aortic tissue; in group B, saphenous vein-derived cells were used. Analysis included histology, electron microscopy, mechanical testing, and biochemical assays for cell proliferation (DNA) and extracellular matrix (collagen). DNA content was comparable in both groups. Collagen and stress at maximum load was significantly higher in group B. Morphology showed viable, layered cellular tissue in all samples, with collagen fibrils most pronounced in group B. In conclusion, saphenous vein myofibroblasts cultured on biodegradable scaffolds showed excellent in vitro tissue generation. Collagen formation and mechanical properties were superior to aortic tissue derived constructs. Therefore, the easy-to-access vein cells represent a promising alternative cell source for cardiovascular tissue engineering.

Tissue engineering of small caliber vascular grafts.

OBJECTIVE: Previous tissue engineering approaches to create small caliber vascular grafts have been limited by the structural and mechanical immaturity of the constructs. This study uses a novel in vitro pulse duplicator system providing a 'biomimetic' environment during tissue formation to yield more mature, implantable vascular grafts. METHODS: Vascular grafts (I.D. 0.5 cm) were fabricated from novel bioabsorbable polymers (polyglycolic-acid/poly-4-hydroxybutyrate) and sequentially seeded with ovine vascular myofibroblasts and endothelial cells. After 4 days static culture, the grafts (n=24) were grown in vitro in a pulse duplicator system (bioreactor) for 4, 7, 14, 21, and 28 days. Controls (n=24) were grown in static culture conditions. Analysis of the neo-tissue included histology, scanning electron microscopy (SEM), and biochemical assays (DNA for cell content, 5-hydroxyproline for collagen). Mechanical testing was performed measuring the burst pressure and the suture retention strength. RESULTS: Histology showed viable, dense tissue in all samples. SEM demonstrated confluent smooth inner surfaces of the grafts exposed to pulsatile flow after 14 days. Biochemical analysis revealed a continuous increase of cell mass and collagen to 21 days compared to significantly lower values in the static controls. The mechanical properties of the pulsed vascular grafts comprised supra-physiological burst strength and suture retention strength appropriate for surgical implantation. CONCLUSIONS: This study demonstrates the feasibility of tissue engineering of viable, surgically implantable small caliber vascular grafts and the important effect of a 'biomimetic' in vitro environment on tissue maturation and extracellular matrix formation.

L-arginine polymers inhibit the development of vein graft neointimal hyperplasia.

OBJECTIVE: We sought to determine whether L -arginine polymer treatment of vein grafts enhances vascular production of nitric oxide and inhibits the development of neointimal hyperplasia. METHODS: External jugular veins of New Zealand White rabbits (n = 42) were harvested; treated intraluminally for 15 minutes with phosphate-buffered saline solution or L -arginine polymer 5, 7, or 9 at either 10 or 100 micromol/L; and then grafted into the contralateral carotid artery. Rabbits were killed after 28 days, and 5-microm sections of vessels were stained with hematoxylin and scored for intima/media ratio by using computerized morphometric analysis. Separate veins were treated in a similar fashion with biotinylated polymers and phosphate-buffered saline solution to assess for translocation efficiencies. Finally, vein segments pretreated with either phosphate-buffered saline solution or L -arginine polymers were cultured in Dulbecco's modified Eagle's medium containing lipopolysaccharide (100 microg/mL) and interferon gamma (200 U/mL) for 48 hours before measuring nitric oxide levels by means of the Griess reaction. RESULTS: Biotinylated L -arginine polymers demonstrated a dose- and length-dependent uptake into intimal and medial cells of treated vessels. Nitric oxide levels were significantly higher in vein segments treated with 100 micromol/L of L -arginine polymer 9 compared with control segments. Finally, the intima/media ratio also reflected both length- and concentration-dependent inhibition of neointimal hyperplasia.intima/media ratio PBS R5 R7 R9 10 micromol/L 0.909 +/- 0.072 0.920 +/- 0.073 0.861 +/- 0.138 0.710 +/- 0.122 100 micromol/L 0.924 +/- 0.061 0.581 +/- 0.089* 0.529 +/- 0.093* PBS, Phosphate-buffered saline solution; R, L -arginine polymer. *P <.001 versus phosphate-buffered saline solution and L -arginine polymer 5 controls (Bonferroni-corrected value). CONCLUSIONS: Arginine polymers of sufficient length and concentration were effective in increasing nitric oxide levels and reducing neointimal hyperplasia in this vein graft model.

Heat shock protein upregulation lowers cytokine levels after ischemia and reperfusion.

OBJECTIVE: Studies showed that the expression of heat shock protein 70 (HSP70) by whole-body hyperthermia or warming of the heart is associated with protection against ischemia/reperfusion injury. The aim of this study is to determine a time-related response of HSP70 expression through topical cardiac warming with correlation to cytokine production. METHODS: 30 rats were divided into three groups: no heat shock, heat shocked, and controls. Heat shock was performed with 42 degrees C saline solution applied to the heart for 5, 30, and 60 min. HSP70 and cytokines were measured. RESULTS: Heat shock treated animals showed a 1.2-fold increase after 5 min (NS) in HSP70 expression, a 2.0-fold increase (p < 0.02) after 30 min, and a 2.3-fold increase (p < 0.012) after 60 min compared to controls. The IL-1beta levels decreased from 14.3 pg/ml (normal controls) to 7.1 pg/ml after 5 min, to 1.6 pg/ml after 30 min (p < 0.002), and to 1.4 pg/ ml after 60 min of heat shock treatment (p < 0.002). The TNF-alpha levels also decreased, but not significantly. CONCLUSIONS: Upregulation of HSP70 through this novel method is instant and detectable within hours. The amount of HSP70 expression induced is time dependent, showing an indirect correlation with cytokine levels. These results suggest that the protective effect of HSP70 is immediate and might be explained by reduced cytokine levels. No prior recovery period is needed.

Long-term results and determinants of mortality after surgery for native and prosthetic valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: The study aim was to describe the long-term results and determinants of mortality after operative treatment of native and prosthetic valve endocarditis at a single institution. METHODS: Between March 1985 and October 1999, 171 patients underwent surgery for native (NVE) or prosthetic valve endocarditis (PVE). NVE was present in 98 patients (57%), and PVE in 73 patients (43%). Mean follow up was 5.6+/-3.9 years (range: 0 to 15 years). RESULTS: Overall hospital mortality was 9.9% (n = 17). Hospital mortality was higher among patients with PVE (15.1%) than those with NVE (6.1%; p = 0.05). Overall survival at 10 years was 46+/-5%. Patients with NVE had a higher 10-year survival rate (53+/-7%) than those with PVE (37+/-7%; p = 0.02). At 10 years, overall freedom from any late complication was 47+/-6% and from residual or recurrent endocarditis was 78+/-5%. Predictors of hospital death were emergency surgery (p <0.003) and preoperative renal insufficiency (p <0.008). Predictors of late death were age >70 years (p <0.002), renal failure (p <0.03) and fungal endocarditis (p <0.04). CONCLUSION: These findings demonstrate the increased perioperative, as well as postoperative, risks associated with PVE versus NVE. Cardiac and extracardiac manifestations of the disease, as well as fungal organisms, but not the activity of the endocarditis, were significant adverse determinants of late outcome.