Off-pump coronary bypass surgery adversely affects alveolar gas exchange

While the introduction of off-pump myocardial revascularization (OPCAB) has initially shown promise in reducing respiratory complications inherent to conventional coronary surgery, it has failed to eradicate them. Our study focused on quantifying the lactate release from the lungs and the dysfunction at the level of the alveolar-capillary membrane precipitated by OPCAB at different time points after the insult. Furthermore, we aimed to determine the impact of pulmonary lactate production on systemic lactic acid concentrations. The study was conducted in a prospective observational fashion. Forty consecutive patients undergoing OPCAB were analyzed. The mean patient age was 60 +/- 10 years. The mean EUROScore was 3.8 +/- 2.9. The alveolar-arterial O2 gradient increased from 19 [range 9 to 30] to 26 [range 20 to 34] kPa (P < 0.001) and remained elevated up to 6 hours after surgery. It rapidly declined again by 18 hours postoperatively. The observed increase in the pulmonary lactate release (PLR) from a baseline value of 0.022 [range -0.074 to 0.066] to 0.089 [range 0.016 to 0.209] mmol/min/m2 at six hours postoperatively did not reach statistical significance (P = 0.105). The systemic arterial lactate (Ls) concentration increased from 0.94 [range 0.78 to 1.06] to 1.39 [range 0.97 to 2.81] mmol/L (P < 0.001). The venoarterial pCO2 difference showed no significant change in comparison to baseline values. The mortality in the studied group was 2.5% (1/40). The pulmonary lactate production showed a statistically significant correlation with the systemic lactate concentration (R = 0.46; P = 0.003). Pulmonary injury following off pump myocardial revascularization was evidenced by a prompt increase in the alveolar-arterial oxygen gradient. The alveolar-arterial O2 gradient correlated with the duration of mechanical ventilation

Rezultati ugradnje Levitronix Centrimag mehaničke potpore srcu u Kliničkom bolničkom centru Zagreb

Background: The management of end stage heart failure has been revolutionized by the use of mechanical circulatory support. The Levitronix Centrimag ventricular assist device (VAD) is designed for short-term cardiac assistance as a bridge to a more permanent solution to the hemodynamic problem. It has been used as bridge-to-transplantation, bridge-to-bridge, bridge-to-recovery, and bridge-to-decision. Methods: In the period between September 2008 and November 2009, six patients received mechanical cardiac assistance with the Levitronix Centrimag device at our institution. In one patient, the indication was postcardiotomy cardiogenic shock. In the remaining five patients, the device was implanted electively, due to progressive decompensation of chronic heart failure unresponsive to medical therapy. Results: The patient having received a biventricular assist device (BIVAD) in the postcardiotomy setting was 65 years of age. His ejection fraction and EuroSCORE were 20 % and 25, respectively. His NT-pro-BNP was 9,428 pg/ml and his pre-implantation lactate was 8.8 mmol/L. The mean age in the group of patients, in whom the VAD was placed due to decompensated severe heart failure (DSHF ), was 46 ± 11 years. Their ejection fraction and logistic EuroSCORE were 16 ± 2 % and 28 ± 7, respectively. The preoperative serum lactate and NT-pro-BNP concentrations were 1.7±0.8 mmol/L and 9577 ± 3674 pg/ml, respectively. Of these, three patients had evidence of end organ dysfunction. The low cardiac output was responsible for acute renal failure, requiring renal replacement therapy in one patient. Neurocognitive dysfunction and renal failure not requiring dialysis was seen in another. The third patient had long standing primary hepatic insufficiency. A reversal of end organ dysfunction was seen in the former two patients, whereas the hepatic insufficiency was not caused by hemodynamic compromise and was, therefore, not relieved by circulatory support. The single patient, who had suffered from postcardiotomy cardiogenic shock, died shortly after receiving mechanical circulatory support. Three of five patients, in whom Levitronix Centrimag was placed electively, were successfully transplanted. The remaining two died of septic complications. In the cohort of patients, in whom ventricular assistance was placed due to DSHF , two required BIVAD placement, and three left ventricular assist devices (LVAD). Conclusion: The Levitronix Centrimag VAD is useful in supporting circulation in patients with acute decompensation of congestive heart failure. It may also be used in patients with postcardiotomy shock. It is an imperative for the device to be placed before irreversible organ dysfunction occurs as the aftermath of malperfusion.Uvod: Liječenje terminalne faze srčanog popuštanja je revolucionarizirano uvođenjem mehaničke potpore srcu. Levitronix Centrimag je uređaj dizajniran u svrhu kratkoročne hemodinamske potpore prije nego što trajnije rješenje cirkulatornog problema postane moguće. Do sad se primijenjivao kao podrška srcu do transplantacije srca, do oporavka srčane funkcije ili do ugradnje trajnijeg oblika mehaničke potpore srcu. Metode: U periodu između rujna 2008 i studenog 2009 Levitronix Centrimag je u našoj ustanovi ugrađen u 6 bolesnika. U jednog bolesnika radilo se o postkardiotomijskom sindromu niskog minutnog volumena. U preostalih pet bolesnika ovaj je oblik mehaničke potpore srcu ugrađen elektivno radi progresivnog kliničkog pogoršanja bolesnika u terminalnoj fazi srčanog popuštanja koje je postalo rezistentno na konzervativnu terapiju. Rezultati: Bolesnik u kojeg je indikacija za mehaničkom potporom srcu bila postavljena hitno u postkardiotomijskom srčanom popuštanju bio je 65 godina star. Imao je ejekcijsku frakciju od 20% dok mu je logistički EuroSCORE bio 25. Prijeoperacijski NT-pro-BNP bio je 9428 pg/ ml dok su serumske vrijednosti laktata prije implantacije Centrimaga bile 8.8 mmol/L. Prosječna dob u skupini bolesnika u kojih je indikacija za mehaničku potporu srcu bila progresivna dekompenzacija srčane funkcije bila je 46 ± 11 godinu. Navedeni bolesnici su imali prosječnu ejekcijsku frakciju od 16 ± 2% dok im je logistički EuroSCORE bio 28 ± 7. Prijeoperacijske vrijednosti serumskog laktata i NT-pro-BNP bile su 1.7±0.8 mmol/L i 9577 ± 3674 pg/ml. U troje bolesnika bila je evidentna kompromitacija funkcije nekog od ostalih organskih sustava. U jednog bolesnika se radilo o akutnom renalnom zatajenju ovisnog o hemodijalizi, u drugog o neurokognitivnoj disfunkciji praćenog sa bubrežnim zatajenjem ali bez potrebe za dijalizom. U trećeg bolesnika radilo se o primarnoj hepatalnoj insuficijenciji. U prva dva bolesnika došlo je do poboljšanja organskih funkcija nakon uspostave mehaničke potpore srcu, dok u trećeg bolesnika nije došlo do promjene hepatalne funkcije budući da ista nije bila uzrokovana malperfuzijom. Bolesnik u kojeg je mehanička potpora srcu stavljena zbog postkardiotomijskog kardiogenog šoka je umro. Troje od pet bolesnika kod kojih je Levitronix Centrimag ugrađen radi dekompenzacije kroničnog zatajenja srca su uspješno transplantirani. Preostalo dvoje bolesnika je umrlo od septičnih komplikacija. U kohorti bolesnika u kojoj je mehanička potpora srcu ugrađena elektivno, dvoje bolesnika je zahtijevalo potporu oba ventrikula dok je u troje ugrađena potpora samo lijevom. Zaključak: Levitronix Centrimag pruža efikasnu hemodinamsku potporu bolesnicima sa kompromitiranom srčanom funkcijom. Neophodno je započeti sa mehaničkom potporom srcu prije nego što se pojave ireverzibilne disfunkcije ostalih organskih sustava

Postoperative atrial fibrillation is associated with high on-aspirin platelet reactivity

BACKGROUND: Atrial fibrillation (AF) contributes to a prothrombotic state through platelet activation. It is unclear whether increased platelet aggregability in patients with AF is caused by the underlying cardiovascular condition rather than the arrhythmia per se. We investigated the effect of postoperative atrial fibrillation (POAF) on platelet reactivity after coronary artery bypass grafting (CABG). ----- METHODS: This study is a post hoc analysis from a randomized controlled trial (ClinicalTrials.gov: NCT01159639) based on patients undergoing elective primary CABG. Patients were dichotomized according to POAF. Postoperative platelet function testing with arachidonic acid as the platelet agonist (ASPI test) was used to define high on-aspirin platelet reactivity (HAPR). ΔASPI presented the difference between pre- and postoperative ASPI test values. To account for the isolated effect of POAF on platelet reactivity, a propensity score analysis was applied. ----- RESULTS: Overall incidence of POAF was 23% (92 of 398 patients). HAPR was detected in 54% (214 of 398) of patients. HAPR was more prevalent among patients with POAF when compared with patients without POAF (64.1% versus 50.7%; odds ratio [OR], 1.74; 95% confidence interval [CI], 1.08-2.82; p = 0.023). The propensity score model produced a subcohort of patients that was well balanced for comorbidities. When compared with the matched group without POAF, the POAF group maintained its prevalence for HAPR (64.1% versus 45.7%; OR, 2.13; 95% CI, 1.18-3.85; p = 0.012) and had greater ΔASPI values (15.0 [IQR, 0.0-36.0] vs 8.0 [IQR, -5.5-19.5]; p = 0.030). ----- CONCLUSIONS: The main finding of our study indicates there is added platelet activation in patients with POAF after CABG before and after controlling for pathologic conditions through propensity matching. The present study does not prove a causal association between POAF and HAPR