[Cognitive deterioration after cardiosurgery]. / Kognitive Störungen nach kardiochirurgischen Eingriffen.

Over 100,000 heart surgeries are performed in Germany annually. Although severe neurological complications like ischaemic strokes have meanwhile become rare occurrences, subtle neuropsychological changes are still frequently recognized after major heart surgeries. The hitherto unsolved problem of postoperative cognitive decline (POCD) is portrayed in this article. Multifactorial aetiologies including microembolism and preoperative risk factors are supposed to play a significant role in POCD. A variety of neuroprotective strategies such as intraoperative microemboli filtration have been suggested to minimize cerebral risks. The utility of neuroprotective methods has recently been verified in randomized studies.

Measurement of myocardial oxygen tension: a valid and sensitive method in the investigation of transmyocardial laser revascularization in an acute ischemia model.

BACKGROUND: The effect of transmyocardial laser revascularization (TMLR) on microperfusion and oxygen supply was studied in an acute ischemia model, using 35 pigs, with 13 serving as controls. METHODS: Measurement of tissue oxygen tension was compared with the semiquantitative measurement of microperfusion using contrast echocardiography and infrared laser Doppler. All methods were used before and after coronary occlusion and after TMLR. Effects were measured in the ischemic area and in two ischemia independent areas. RESULTS: At baseline, oxygen partial pressure was 54.2 +/- 15.7 mmHg and decreased to 2.8 +/- 1.4 mmHg ( P < 0.05) after occlusion. After TMLR, oxygen tension increased to 27.3 +/- 8.5 mmHg ( P < 0.05) in the ischemic area, indicating a significant effect of TMLR on microperfusion and oxygen tension. Changes in regional oxygen tension corresponded to Levovist density changes in contrast echocardiography and changes in microperfusion measured by infrared laser Doppler. CONCLUSIONS: Our data indicate that measurement of tissue oxygen tension is a suitable experimental tool to assess the effect of TMLR on myocardial perfusion, which cannot be discriminated using clinical imaging methods.

Preexisting atrial fibrillation as predictor for late-time mortality in patients with end-stage renal disease undergoing cardiac surgery--a multicenter study.

BACKGROUND: Although patients with end-stage renal disease (ESRD) are considered to be high-risk patients in cardiac surgery, the reported studies are rather small, resulting in unsatisfactory analyses of outcome determinants. Therefore, we aimed to identify possible risk factors, with a particular focus on the impact of pre-existing atrial fibrillation (AF) on the postoperative short-term and long-term mortality of ESRD patients undergoing cardiac surgery. METHODS: In a multicenter study 522 patients with ESRD undergoing CABG only (62.9 %), valve surgery only (17.2 %), or both (19.9 %) with comparable demographic and other cardiac risk factor characteristics were investigated retrospectively over a period of 10 years. The outcome was divided into perioperative (within 30 days) and late morbidity and mortality, and multivariate analysis was performed for both. RESULTS: The mean perioperative mortality was 11.5 % and the 5-year survival rate was 42 %. Emergency surgery, insulin-dependent diabetes mellitus, the number of vein grafts and age were identified as risk factors whereas complete revascularization, the use of an internal thoracic artery and the presence of sinus rhythm were identified as beneficial factors for long-term survival. 14.1 % of all patients had pre-existing AF. Although AF was not identified as an independent risk factor for perioperative mortality ( P = 0.59), it was identified as an independent predictor for late mortality ( P < 0.001). Median survival of patients without AF was 1816 days, while for patients with AF it was only 715 days. CONCLUSIONS: AF does represent an independent predictor for long-term but not perioperative mortality in patients with ESRD. However, effective treatment of AF is controversially discussed. Anticoagulation therapy or perioperative ablation of the arrhythmia should be considered in order to improve the survival of these patients.

Reduction of gaseous microembolism during aortic valve replacement using a dynamic bubble trap.

Serious postoperative psycho-neurological dysfunction is at least partially attributed to the occurrence of gaseous microbubbles in the arterial line of extracorporeal circulation (ECC). Therefore, we investigated in a prospective randomized double blind study whether the usage of dynamic bubble trap (DBT) will reduce microbubble load of patients undergoing aortic valve replacement. Patients (n = 41) were divided into group I (GI, n = 22) with DBT introduced into the arterial line of ECC and group II (GII, n = 19) with placebo-DBT instead. Doppler ultrasonography was used for detection of microbubbles before and after DBT, and for detection of high intensity transient signals (HITS) within the middle cerebral artery. The recording time during ECC was divided into period 1 (P1, until aortic clamp removal) and period 2 (P2, clamp removal until the end of ECC). A significant reduction of microbubble load was found in GI only (p < 0.0001 for ECC; p < 0.0001 for P1; p < 0.0025 for P2). A significant difference in number of HITS between the groups was observed in P1 only (p < 0.002 left middle cerebral artery, p < 0.005 right middle cerebral artery), since in P2 the trapped air in left chamber can go to the supraaortal vessels without passing ECC. In conclusion the use of DBT cannot substitute careful venting after aortic declamping. Nevertheless, reduction of HITS in the cross-clamped period of ECC justifies the use of DBT in patients undergoing open chamber surgery.

Contrast echocardiography: a valid and sensitive imaging method in the investigation of transmyocardial laser-revascularization in an acute ischemia model.

In an acute porcine myocardial ischemia model we examined the effect of transmyocardial laser-revascularization (TMLR) on the regional micro perfusion and oxygen supply. In clinical practice, contrast echocardiography is a reliable tool for the measurement of changes in regional blood flow in the ischemic myocardium. We compared contrast echocardiography with the laser Doppler measurement of micro perfusion and with the quantification of regional tissue oxygen tension using a Clark electrode. 22 pigs were randomised in the interventional group and 12 in the control group. Measurements with all three methods were performed before and after occlusion of the first diagonal branch of the left anterior descending coronary artery and, in the interventional group, after TMLR. We investigated not only the effects in the dependent ischemic myocardium, but also in two other myocardial areas, not involved in the coronary occlusion. There was a significant effect of TMLR on regional micro perfusion and local oxygen tension in the dependent ischemic myocardial area. Contrast echocardiography is a successful experimental tool to measure changes in regional myocardial perfusion which cannot be perceived using clinical imaging methods.

Non-aneurysmal inflammation of the aorta in combination with aortic valve disease.

A 61-year-old man presented with aortic valve stenosis, coronary artery disease in combination with rheumatic arthritis, peri-aortic inflammation and fibrosis with aortitis. In the pathological literature this has been termed chronic periaortitis, while in the surgical literature, non-aneurysmal dilatation of the aorta associated with atherosclerosis and inflammation has been described as aortitis. The name chronic periarteritis refers to the associated involvement of coronary arteries. Although different terminologies have been used, it is suggested that all of them most likely represent the same disease entity.

[Indirect MR venography: contrast medium protocols, postprocessing and combination in diagnosing pulmonary emboli with MRI]. / Indirekte MR-Phlebografie: Kontrastmittelprotokolle, Nachverarbeitung und Kombination mit Lungenemboliediagnostik in der MRT.

PURPOSE: Integration of MR venography in a comprehensive MR imaging protocol in patients with suspected pulmonary embolism (PE) and evaluation of contrast media dosage, timing and postprocessing for diagnostic accuracy. MATERIALS AND METHODS: Forty-eight consecutive inpatients with suspected PE or deep vein thrombosis were examined by MR venography according to one of the following protocols: protocol I: MR venography only, 0.25 mmol/kg body weight (BW) Gadopentate dimeglumine (Gd-DTPA) as single dose, bolus timing; protocol II: MR angiography of pulmonary arteries with a cumulative dosage of 0.25 mmol/kg contrast media, modification of coil setting for MR venography without further contrast media application; protocol III: as protocol II but with 0.125 mmol/kg BW, followed by MR venography. Signal-to-noise ratio, contrast-to-noise ratio, number of definable vascular segments and image quality were evaluated. The results were compared to conventional bilateral venography. RESULTS: All MR venography examinations were of diagnostic quality and the examination time was below 10 min. MR venography could be performed in all 48 patients compared to 43 of 48 patients for conventional venography. Significantly more superficial and deep veins of the leg could be visualized by MR venography (94 % compared to 83 % for conventional venography). Sensitivity and specificity were 100 % and 92 %, respectively. Quality differed significantly between 0.125 mmol/kg (protocol III) and 0.25 mmol/kg Gd-DTPA (protocols I and II) while timing did not influence quality (protocol I vs. II). CONCLUSION: An integrated MR diagnostic evaluation of pulmonary arteries and veins of the leg is feasible in patients with suspected PE. MR venography with 0.25 mmol/kg Gd-DTPA reliably depicts the venous system of the leg more completely than conventional venography with at least equivalent diagnostic confidence.

Intracellular adhesion molecule-1 in patients developing pulmonary insufficiency after cardiopulmonary bypass.

OBJECTIVES: Cardiopulmonary bypass activates adhesion molecules, which are associated with systemic inflammation and organ dysfunction. The intracellular adhesion molecule-1 (ICAM-1) has been evaluated in patients presenting pulmonary dysfunction after cardiac surgery. MATERIALS AND METHODS: Postoperative serum levels of the ICAM-1 were measured in 40 patients who underwent isolated coronary artery bypass grafting, in 28 with uneventful postoperative recovery (70 %) (Group 1), and in 12 (30 %) with postoperative respiratory insufficiency (Group 2), defined by the need for prolonged (> 24 hours) mechanical ventilation using a fractional oxygen concentration of > 40 %. RESULTS: Patients in group 1 were ventilated for 12.21 +/- 4.86 hours and those in group 2 for 92.91 +/- 48.14 hours (p < 0.001). ICAM-1 decreased from 145.98 +/- 73.40 ng/ml to 81.15 +/- 114.82 ng/ml in group 1, while in group 2 ICAM-1 showed a significant higher level and increased to 435.01 +/- 130.02 ng/ml (p < 0.001). The leukocyte count increased in both groups as well as the C-reactive protein (CRP) during the postoperative course. The CRP behaves similar in both groups (p = 0.636) in contrast to the leukocyte count which was significantly higher in group 2 (p < 0.01). While none of the patients in group 1 died the mortality in group 2 was 50 % (p < 0.001). CONCLUSION: Respiratory insufficiency after cardiopulmonary bypass is associated with a distinct increase in the ICAM-1. The reason for the increase of the ICAM-1 in this small subset of patients has not been clarified.

[Papillary muscle rupture after mitral valve replacement with preservation of subvalvular structures]. / Papillarmuskelruptur nach Mitralklappenersatz mit erhaltenem subvalvulärem Apparat.

We report a female patient with mitral valve replacement and preservation of subvalvular apparatus in which parts of the papillary muscle ruptured postoperatively. During systole the ruptured papillary muscle prolapsed through the native aortic valve. Echocardiographic documentation and operative procedure were demonstrated.

Thrombotic formations within the aortic arch as source of embolization in patients with coagulopathia.

Thrombotic formations on atherosclerotic lesions of the thoracic aorta are potential sources of cerebral and systemic embolization. Especially younger patients without calcifications of atherosclerotic plaques or coagulation disorders have a higher risk for embolization. Magnetic resonance imaging and transesophageal echocardiography are the diagnostic methods of choice. As an alternative to anticoagulation surgical therapy is indicated to prevent severe brain damage or multiorgan failure in patients with mobile thrombotic formations. Herein we describe two patients in whom successful surgical treatment was performed in deep hypothermic circulatory arrest by excision of the aortic arch atheroma.

Significant reduction of air microbubbles with the dynamic bubble trap during cardiopulmonary bypass.

Air microbubbles mostly occur unnoticed during cardiopulmonary bypass and are predominantly responsible for serious postoperative psychoneurological dysfunction. A dynamic bubble trap (DBT), which removes air microbubbles from the arterial blood, was tested in a clinical study. The aim was to evaluate the efficiency of microbubble removal under clinical conditions. As blood passes through the DBT, which is placed in the arterial line between the arterial filter and arterial cannula, it is converted into a rotating stream. The bubbles are directed to the centre of the blood flow and are collected in the distal end of the DBT, from where they are returned to the cardiotomy reservoir. Doppler ultrasonography was used to detect the microbubbles before and after the DBT, and also the number of high-intensity transient signals (HITS) in the right and left middle cerebral artery during extracorporeal circulation. A significant reduction of microbubbles in the arterial line (3,990 before DBT, 537 after, p < 0.001) and HITS in the brain (51 in the DBT group, 77 in the placebo group, p = 0.04) was measured.

Simvastatin attenuates vascular hypercoagulability in cardiac transplant recipients.

BACKGROUND: 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to reduce cardiac allograft failure and to lower the incidence of transplant coronary artery disease. These effects result from as yet unknown mechanisms not clearly attributable to lipid lowering. We here report that low-dose simvastatin treatment inhibits excessive expression of monocyte tissue factor (TF) and reduces the persistent hypercoagulability state seen in cardiac transplant recipients. METHODS: Fifteen consecutive heart transplant recipients receiving standard oral immunosuppression were newly assigned to a 10 mg daily simvastatin therapy. Levels of TF activity in both unstimulated and lipopolysaccharide-stimulated peripheral blood mononuclear cells drawn from transplant recipients before and under simvastatin therapy were evaluated by one-stage clotting assay. RESULTS: Monocyte TF activity was found to be significantly increased in cardiac transplant recipients when compared with healthy controls. Excessive monocyte procoagulant activity was reduced in cardiac transplant recipients during simvastatin treatment. This effect occurred independently of the reduction of serum low-density lipoprotein cholesterol. As demonstrated by reverse transcriptase-polymerase chain reaction, monocyte TF reduction by simvastatin, observed in 13 of the 15 transplant recipients investigated, could be ascribed to an inhibition of monocyte TF gene transcription. The reduction of monocyte TF activity during treatment with simvastatin paralleled with the normalization of elevated levels of thrombin-antithrombin complex, prothrombin fragment F1+2, and D-dimer, which are markers of thrombin and fibrin formation indicating coagulation activation after cardiac transplantation. CONCLUSION: Inhibition of monocyte TF expression and attenuation of the persistent hypercoagulable state observed in cardiac transplant recipients during treatment with simvastatin may represent an important mechanism by which HMG-CoA reductase inhibitors protect against the development of transplant coronary artery disease.

A dynamic bubble trap reduces microbubbles during cardiopulmonary bypass: a case study.

Microemboli passing to the cerebral circulation during cardiopulmonary bypass can contribute to postoperative neurologic dysfunction. Many studies conclude that air microbubbles predominantly are responsible for this problem. A dynamic bubble trap (DBT) was developed to diminish the number of microbubbles in the arterial line of extracorporeal circulation. The DBT is able to substantially reduce the number of air microbubbles, as shown in two patients undergoing coronary artery bypass grafting, where a high number of microbubbles was assessed. Although a 40-micron arterial filter was used, many bubbles larger than 40 microns occurred in the arterial line. The DBT reduced the number of large microbubbles from 2,267 to 67 in patient 1 and from 897 to 61 in patient 2.

High-dose enoximone to evaluate reversibility of pulmonary hypertension: is there a diagnostic value of neurohormonal measurements?

BACKGROUND: Heart transplantation is associated with a reduction of the neurohumoral activation seen in patients with severe congestive heart failure. In this study, we investigated whether pharmacologically induced complex hemodynamic improvement during assessment of reversibility of pulmonary hypertension with a phosphodiesterase inhibitor is able to induce neurohormonal changes of diagnostic importance. METHODS AND RESULTS: Twenty-one patients with New York Heart Association class III-IV heart failure underwent infusion of 3 mg/kg enoximone over a period of 30 minutes. Before and after drug infusion, we determined the plasma concentrations of atrial natriuretic peptide, endothelin-I, angiotensin-II, aldosterone, norepinephrine, epinephrine, and angiotensin-converting enzyme activity sampled from a peripheral vein and the pulmonary artery. In addition to the expected significant reduction of pulmonary hypertension and enhancement of cardiac output, increased levels of the vasoconstrictors endothelin-I, angiotensin-II, and norepinephrine were observed. Aldosterone fell after enoximone infusion; a higher baseline aldosterone level correlated to the degree of reduction of the pulmonary arteriolar resistance by enoximone. Baseline atrial natriuretic peptide levels correlated with parameters, indicating the severity of heart failure. However, the plasma concentration of this peptide did not change significantly after enoximone infusion. CONCLUSIONS: Acute hemodynamic improvement after enoximone bolus in candidates for heart transplantation is not accompanied by a reduction of the enhanced neurohumoral activity in these patients. The reaction of the investigated hormones cannot predict the individual degree of reversibility of pulmonary hypertension.

Valve surgery combined with coronary artery operation: is the use of internal mammary artery a predictor for early complications?

The internal mammary artery (IMA) provides better early and long-term patency than venous grafts do. Although IMA is the conduit of choice in isolated coronary artery bypass grafting (CABG), its use in combined procedures is not routine in some cardiovascular units. During a 16-month period, 188 patients underwent valve surgery combined with CABG. Internal mammary grafts were used in 68/188 (36%) patients (group 1) and vein grafts without arterial grafts (group 2) in 120/188 (64%). Left IMA was implanted in 67/68 (99%) and right IMA in 1/68 1%) cases. Surgeon A used IMA in 28/44 (64%), surgeon B in 20/32 (63%), surgeon C in 18/44 (41%), surgeon D in 1/4 (25%) and surgeon E in 1/63 (2%) patients. The final decision to use IMA in a combined procedure was left up to the surgeon. Statistically, the preoperative- and perioperative data were identical in the two groups, although the frequency of IMA grafting in patients with double valve replacement and reoperation was lower (1/68 vs 11/120, ns, and 3/68 vs 9/120, ns). Ten of 188 (5.3%) patients died within 30 days after operation. Longer cross-clamp time (P = 0.008) and mitral valve replacement (P = 0.05) were independent risk factors for early death. The use of IMA did not increase the risk of early mortality. The postoperative variables were similar in the IMA and vein groups, in particular data suggesting perioperative myocardial infarction (CK-MB, catecholamine support). Postoperative mechanical ventilation was longer in the IMA group, although not significantly (P = 0.06). Early mortality and morbidity were identical in the two groups in combined procedures. We did not find any hints for an increased risk of using IMA in this type of surgery. Internal mammary artery implantation is safe in selected patients undergoing combined valve and CABG surgery. Beside the better long-term patency of IMA, its use may have several technical advantages.