Hilmar Dörge

Impact of preoperative statin therapy on adverse postoperative outcomes in patients undergoing cardiac surgery: a meta-analysis of over 30 000 patients

AIMS To determine the strength of evidence for preoperative statin use for prevention of adverse postoperative outcomes in patients undergoing cardiac surgery. METHODS AND RESULTS After literature search in major databases, 19 studies were identified [three RCT (randomized prospective clinical trials), 16 observational] that reported outcomes of 31 725 cardiac surgery patients with (n = 17 201; 54%) or without (n = 14 524; 46%) preoperative statin therapy. Outcomes that were analysed included early all-cause mortality (30-day mortality), myocardial infarction (MI), atrial fibrillation (AF), stroke and renal failure. Odds ratio (OR) with 95% confidence intervals (95%CI) were reported using fixed or random effect models and publication bias was assessed. Preoperative statin therapy resulted in a 1.5% absolute risk reduction (2.2 vs. 3.7%; P < 0.0001) and 43% odds reduction for early all-cause mortality (OR 0.57; 95%CI: 0.49-0.67). A significant reduction (P < 0.01) in statin pretreated patients was also observed for AF (24.9 vs. 29.3%; OR 0.67, 95%CI: 0.51-0.88), stroke (2.1 vs. 2.9%, OR 0.74, 95%CI: 0.60-0.91), but not for MI (OR 1.11; 95%CI: 0.93-1.33) or renal failure (OR 0.78, 95%CI: 0.46-1.31). Funnel plot and Eggers regression analysis (P = 0.60) excluded relevant publication bias. CONCLUSION Our meta-analysis provides evidence that preoperative statin therapy exerts substantial clinical benefit on early postoperative adverse outcomes in cardiac surgery patients, but underscores the need for RCT trials.

Infarct size reduction by AT1-receptor blockade through a signal cascade of AT2-receptor activation, bradykinin and prostaglandins in pigs ☆

OBJECTIVE We studied the effect of the angiotensin II type 1 (AT1)-receptor antagonist candesartan on infarct size resulting from regional myocardial ischemia in pigs. BACKGROUND The effects of AT1-receptor blockade on infarct size in different species remain controversial and its potential cardioprotective mechanisms are still unclear. In pigs, infarct development closely resembles that observed in humans. METHODS A total of 62 enflurane-anesthetized pigs underwent a protocol of 90-min low-flow ischemia and 120-min reperfusion. Systemic hemodynamics (micromanometer), regional myocardial function (sonomicrometry), regional myocardial blood flow (microspheres) and infarct size (TTC [triphenyl tetrazolium chloride]-staining) were determined. RESULTS Left ventricular peak pressure decreased with candesartan (1 mg/kg i.v.) from 97+/-2 standard error of the mean (SEM) to 86+/-5 mm Hg and was then readjusted by aortic banding. In placebo pigs (n=9), infarct size was 21.8+/-4.8% of the area at risk. Candesartan (n=7) reduced infarct size to 9.7+/-2.5% (p < 0.05). Pretreatment with the AT2-receptor antagonist PD123319 (3 microg/kg/min intracoronarily [i.c.]; n=8), the bradykinin B2-receptor antagonist HOE140 (0.01 microg/kg/min i.c.; n=8) or the cyclooxygenase inhibitor indomethacin (10 mg/kg i.v.; n= 8) per se did not affect infarct size but did abolish the reduction of infarct size achieved by candesartan (PD123319 + candesartan (n=7): 23.2+/-4.7%; HOE140 + candesartan (n=7): 18.2+/-4.0%; indomethacin + candesartan (n=8): 21.1+/-5.2%). Hemodynamics, regional myocardial blood flow during ischemia and the area at risk were comparable among all groups of pigs. CONCLUSIONS Reduction of infarct size by the AT1-receptor antagonist candesartan in pigs involves angiotensin II type 2 receptor (AT2) activation, bradykinin and prostaglandins.

Myocardial Dysfunction With Coronary Microembolization: Signal Transduction Through a Sequence of Nitric Oxide, Tumor Necrosis Factor-α, and Sphingosine

Coronary microembolization results in progressive myocardial dysfunction, with causal involvement of tumor necrosis factor-&agr; (TNF-&agr;). TNF-&agr; uses a signal transduction involving nitric oxide (NO) and/or sphingosine. Therefore, we induced coronary microembolization in anesthetized dogs and studied the role and sequence of NO, TNF-&agr;, and sphingosine for the evolving contractile dysfunction. Four sham-operated dogs served as controls (group 1). Eleven dogs received placebo (group 2), 6 dogs received the NO synthase inhibitor NG-nitro-l-arginine methyl ester (L-NAME, group 3), and 6 dogs received the ceramidase inhibitor N-oleoylethanolamine (NOE, group 4) before microembolization was induced by infusion of 3000 microspheres (42-&mgr;m diameter) per milliliter inflow into the left circumflex coronary artery. Posterior systolic wall thickening (PWT) remained unchanged in group 1 but decreased progressively in group 2 from 20.6±4.9% (mean±SD) at baseline to 4.1±3.7% at 8 hours after microembolization. Leukocyte count, TNF-&agr;, and sphingosine contents were increased in the microembolized posterior myocardium. In group 3, PWT remained unchanged (20.3±2.6% at baseline) with intracoronary administration of L-NAME (20.8±3.4%) and 17.7±2.3% at 8 hours after microembolization; TNF-&agr; and sphingosine contents were not increased. In group 4, PWT also remained unchanged (20.7±4.6% at baseline) with intravenous administration of NOE (19.5±5.7%) and 16.4±6.3% at 8 hours after microembolization; TNF-&agr;, but not sphingosine content, was increased. In all groups, systemic hemodynamics, anterior systolic wall thickening, and regional myocardial blood flow remained unchanged throughout the protocols. A signal transduction cascade of NO, TNF-&agr;, and sphingosine is causally involved in the coronary microembolization-induced progressive contractile dysfunction.

Twenty years experience with pediatric pacing: epicardial and transvenous stimulation

OBJECTIVE Permanent cardiac pacing in children and adolescents is rare and often occurs by means of epicardial pacing. Based on two decades of experience, operative and postoperative data of patients with epicardial and transvenous pacing were analyzed retrospectively. METHODS Between October 1979 and December 1998, 71 patients (mean age, 5.3+/-4.2, range, 1 day-16.2 years; mean body weight, 18+/-12; range, 8-56 kg) underwent permanent pacemaker implantation. Indications were sinus node dysfunction and atrio-ventricular block following surgery for congenital heart disease (69%), or congenital atrioventricular block (31%). Pacing was purely atrial (1.4%), purely ventricular (73%), ventricular with atrial synchronization (5. 6%), or atrioventricular synchronized (20%). Epicardial pacing was established in 49 (69%), transvenous in 22 (31%) patients. Follow-up was 3.4+/-3.8 years (epicardial) and 3.0+/-4.0 years (transvenous). RESULTS Epicardial leads were implanted in younger patients (mean age: 4.5 vs. 7.0 years, P<0.05) and preferably after surgery induced atrioventricular block (78 vs. 46%, P<0.05). The youngest patient with transvenous pacing was 1.3 years old (weight, 8.5 kg). At implantation epicardial ventricular stimulation threshold at 1.0 ms was 1.07+/-0.46 vs. 0.53+/-0.31 V (transvenous) (P<0.05). The age-adjusted rate of lead-related reoperations was significantly higher in patients with epicardial leads (P<0.05), mainly due to increasing chronic stimulation thresholds resulting in early battery depletion. In three patients who received steroid-eluting epicardial leads initial low thresholds persisted after five month to one years. In two patients with recurrent epicardial threshold increase, steroid-eluting epicardial leads led to good acute and chronic thresholds after nine to 15 month. Two post-operative death (2.8%) were probably due to a dysfunction of the (epicardial) pacing system. CONCLUSIONS Transvenous pacing in the pediatric population is associated with a lower acute stimulation threshold and a lower rate of lead-related complications. If epicardial pacing is necessary (e. g. small body weight, special intracardiac anatomy (e.g. Fontan), impossible access to superior caval vein), steroid-eluting leads may be considered.

Endotoxin and ischemic preconditioning: TNF-α concentration and myocardial infarct development in rabbits

Ischemic preconditioning (IP) and prior exposure to lipopolysaccharides (LPS) reduce infarct size (IS) and serum tumor necrosis factor-α (TNF-α) concentration resulting from myocardial ischemia-reperfusion in rabbits. The decrease in TNF-α might relate to an induced TNF-α inhibitory serum activity (TNF-α-ISA). We analyzed TNF-α and TNF-α-ISA during 30 and 180 min ischemia and reperfusion, respectively, in anesthetized rabbits either untreated ( group 1, n = 7), preconditioned (5 and 10 min ischemia and reperfusion, respectively, group 2, n = 9), or exposed to LPS 72 h before ischemia ( group 3, n = 9). TNF-α-ISA was assessed by coincubating LPS-stimulated rabbit blood with serum of groups 1-3 and measuring TNF-α (WEHI assay). With a comparable area at risk, IS in group 1 was 36.9 ± 11.1 (SD)%, and it was reduced to 13.1 ± 11.6% and 17.3 ± 11.3% (both P < 0.05) in groups 2 and 3, respectively. TNF-α was increased during ischemia-reperfusion in group 1 but remained unchanged in rabbits subjected to IP or LPS. TNF-α-ISA was detected during ischemia-reperfusion in group 2 (29% and 38% of maximum inhibition, respectively) and during baseline, ischemia and reperfusion in group 3 (51%, 46%, 48% of maximum inhibition, respectively) but was absent in group 1. Cardioprotection by IP and LPS is associated with a reduced TNF-α and an induced TNF-α-ISA during ischemia-reperfusion.Ischemic preconditioning (IP) and prior exposure to lipopolysaccharides (LPS) reduce infarct size (IS) and serum tumor necrosis factor-alpha (TNF-alpha) concentration resulting from myocardial ischemia-reperfusion in rabbits. The decrease in TNF-alpha might relate to an induced TNF-alpha inhibitory serum activity (TNF-alpha-ISA). We analyzed TNF-alpha and TNF-alpha-ISA during 30 and 180 min ischemia and reperfusion, respectively, in anesthetized rabbits either untreated (group 1, n = 7), preconditioned (5 and 10 min ischemia and reperfusion, respectively, group 2, n = 9), or exposed to LPS 72 h before ischemia (group 3, n = 9). TNF-alpha-ISA was assessed by coincubating LPS-stimulated rabbit blood with serum of groups 1-3 and measuring TNF-alpha (WEHI assay). With a comparable area at risk, IS in group 1 was 36.9 +/- 11.1 (SD)%, and it was reduced to 13.1 +/- 11.6% and 17.3 +/- 11.3% (both P < 0.05) in groups 2 and 3, respectively. TNF-alpha was increased during ischemia-reperfusion in group 1 but remained unchanged in rabbits subjected to IP or LPS. TNF-alpha-ISA was detected during ischemia-reperfusion in group 2 (29% and 38% of maximum inhibition, respectively) and during baseline, ischemia and reperfusion in group 3 (51%, 46%, 48% of maximum inhibition, respectively) but was absent in group 1. Cardioprotection by IP and LPS is associated with a reduced TNF-alpha and an induced TNF-alpha-ISA during ischemia-reperfusion.

Glucocorticoid Treatment Prevents Progressive Myocardial Dysfunction Resulting From Experimental Coronary Microembolization

Background—The frequency and importance of microembolization in patients with acute coronary syndromes and during coronary interventions have recently been appreciated. Experimental microembolization induces immediate ischemic dysfunction, which recovers within minutes. Subsequently, progressive contractile dysfunction develops over several hours and is not associated with reduced regional myocardial blood flow (perfusion-contraction mismatch) but rather with a local inflammatory reaction. We have now studied the effect of antiinflammatory glucocorticoid treatment on this progressive contractile dysfunction. Methods and Results—Microembolization was induced by injecting microspheres (42-μm diameter) into the left circumflex coronary artery. Anesthetized dogs were followed up for 8 hours and received placebo (n = 7) or methylprednisolone 30 mg/kg IV either 30 minutes before (n = 7) or 30 minutes after (n = 5) microembolization. In addition, chronically instrumented dogs received either placebo (n = 4) or methylprednisolone (n = 4) 30 minutes after microembolization and were followed up for 1 week. In acute placebo dogs, posterior systolic wall thickening was decreased from 20.0±2.1% (mean±SEM) at baseline to 5.8±0.6% at 8 hours after microembolization. Methylprednisolone prevented the progressive myocardial dysfunction. Increased leukocyte infiltration in the embolized myocardium was prevented only when methylprednisolone was given before microembolization. In chronic placebo dogs, progressive dysfunction recovered from 5.0±0.7% at 4 to 6 hours after microembolization back to baseline (19.1±1.6%) within 5 days. Again, methylprednisolone prevented the progressive myocardial dysfunction. Conclusions—Methylprednisolone, even when given after microembolization, prevents progressive contractile dysfunction.

Attenuation of myocardial stunning by the AT1 receptor antagonist candesartan

Abstract The effect of AT1 receptor blockade on myocardial stunning is still somewhat ambiguous. In some prior studies, coronary occlusion was of too long duration such that the effects of infarction and stunning on the recovery of contractile function could not be distinguished. In others, blood pressure was decreased such that the improved wall excursion could be the consequence of reduced afterload and/or of attenuated stunning. The present study, therefore, investigated the effect of the AT1 receptor antagonist candesartan in a pure model of myocardial stunning with controlled systemic hemodynamics. Fourteen anesthetized open-chest dogs were subjected to 15 minutes occlusion of the left circumflex coronary artery (LCx) and 4 hours subsequent reperfusion. Systemic hemodynamics (micromanometer), regional myocardial blood flow (colored microspheres), and posterior wall thickening (PWT, sonomicrometry) were measured, and data were compared between 7 placebo controls (group 1) and 7 dogs receiving 1 mg/kg candesartan i.v. before LCx occlusion (group 2). Left ventricular peak pressure was kept constant by an intra-aortic balloon, and heart rate did not change throughout the protocol. Regional myocardial blood flow was not different between the groups under control conditions, increased in response to candesartan in group 2 (posterior subendocardial blood flow from 0.99 ± 0.18 to 1.57 ± 0.45; p < 0.05 vs. control conditions), but was not different during myocardial ischemia and at 4 hours of reperfusion between the groups. Under control conditions and during myocardial ischemia, PWT was also not different between the groups. At 4 hours of reperfusion, PWT was still depressed in group 1 (−1.5 ± 3.4 % vs. 17.7 ± 5.6 % during control conditions, p < 0.05), whereas PWT had recovered in group 2 (11.4 ± 3.7 % at 4 hours reperfusion vs. 18.3 ± 2.7 during control conditions, NS, p < 0.05 vs. group 1). In conclusion, pretreatment with the AT1 receptor antagonist candesartan improved the functional recovery of reperfused myocardium. This attenuation of myocardial stunning was not based on more favorable systemic hemodynamics or regional myocardial blood flow.

Unique Cardioprotective Action of the New Calcium Antagonist Mibefradil

BACKGROUND Mibefradil is a calcium antagonist with few negative inotropic effects at therapeutic concentrations. METHODS AND RESULTS The effect of mibefradil on infarct size (IS) was compared with those of placebo, amlodipine, and verapamil in 64 anesthetized pigs. In placebo pigs, after 90 minutes of ischemia and 120 minutes of reperfusion, IS (by triphenyl tetrazolium chloride staining) was 15.3+/-10.8% (SD) of the area at risk. Mibefradil (0.60 mg/kg IV) reduced heart rate and left ventricular (LV) pressure, and IS was 1. 9+/-3.9% (P<0.05 versus placebo). Verapamil (0.15 mg/kg IV) also decreased heart rate, LV pressure, and IS (6.1+/-4.2%, P<0.05 versus placebo). Amlodipine (0.20 mg/kg IV) did not alter heart rate, LV pressure, or IS (9.9+/-5.4%, P=NS versus placebo). When heart rate was maintained constant by left atrial pacing and LV pressure was adjusted to that of the placebo group by an intra-aortic balloon, mibefradil still decreased IS (3.8+/-3.0%, P<0.05 versus placebo), but verapamil did not (11.6+/-8.3%, P=NS versus placebo). With glibenclamide infusion, mibefradil no longer reduced IS (13.1+/-4.3% versus 17.8+/-5.6% with glibenclamide alone, P=NS). CONCLUSIONS The IS-limiting effect of mibefradil, in contrast to that of verapamil, was not dependent on favorable hemodynamics but was abolished by glibenclamide, suggesting a direct cardioprotective action of mibefradil.

Surgical treatment of pulmonary aspergillosis/mycosis in immunocompromised patients

Invasive pulmonary aspergillosis is a severe complication in immunosuppressed patients. Surgical resection can be curative in certain patients after antifungal treatment. Over a 7-year period, ten patients with suspected invasive pulmonary aspergillosis of two university hospitals were retrospectively reviewed. A literature review was undertaken. Patients age was 48.1 years (mean); the cause of immunosuppression was a hematological disease with consecutive therapy in seven patients and chronically corticoid therapy in three patients. After an antifungal therapy, surgical resection was performed with lobectomy/segmentectomy in 60% and with wedge-resection in 40%. Postoperative course were uneventful in seven patients, two patients died due to infectional circumstances, and one patient was reoperated because of empyema. The underlying disease marked long-term follow-up. Resection of focal pulmonary invasive aspergillosis can be curative. Clinical circumstances and dissemination must be taken into consideration to indicate surgery. To point out the best pathway randomised prospective studies are necessary.

Angiotensin II and myosin light-chain phosphorylation contribute to the stretch-induced slow force response in human atrial myocardium

AIMS Stretch is an important regulator of atrial function. The functional effects of stretch on human atrium, however, are poorly understood. Thus, we characterized the stretch-induced force response in human atrium and evaluated the underlying cellular mechanisms. METHODS AND RESULTS Isometric twitch force of human atrial trabeculae (n = 252) was recorded (37 degrees C, 1 Hz stimulation) following stretch from 88 (L88) to 98% (L98) of optimal length. [Na(+)](i) and pH(i) were measured using SBFI and BCECF epifluorescence, respectively. Stretch induced a biphasic force increase: an immediate increase [first-phase, Frank-Starling mechanism (FSM)] to approximately 190% of force at L88 followed by an additional slower increase [5-10 min; slow force response (SFR)] to approximately 120% of the FSM. FSM and SFR were unaffected by gender, age, ejection fraction, and pre-medication with major cardiovascular drugs. There was a positive correlation between the amplitude of the FSM and the SFR. [Na(+)](i) rose by approximately 1 mmol/L and pH(i) remained unchanged during the SFR. Inhibition of Na(+)/H(+)-exchange (3 microM HOE642), Na(+)/Ca(2+)-exchange (5 microM KB-R7943), or stretch-activated channels (0.5 microM GsMtx-4 and 80 microM streptomycin) did not reduce the SFR. Inhibition of angiotensin-II (AngII) receptors (5 microM saralasin and 0.5 microM PD123319) or pre-application of 0.5 microM AngII, however, reduced the SFR by approximately 40-60%. Moreover, stretch increased phosphorylation of myosin light chain 2 (MLC2a) and inhibition of MLC kinase (10 microM ML-7 and 5 microM wortmannin) decreased the SFR by approximately 40-85%. CONCLUSION Stretch elicits a SFR in human atrium. The atrial SFR is mediated by stretch-induced release and autocrine/paracrine actions of AngII and increased myofilament Ca(2+) responsiveness via phosphorylation of MLC2a by MLC kinase.