The Association of Matrix Metalloproteinases With Acute Kidney Injury Following CPB-Supported Cardiac Surgery.

BACKGROUND: Cardiac surgery-associated acute kidney injury (AKI) is an adverse outcome that increases morbidity and mortality in patients undergoing cardiac surgical procedures. To date, the use of serum creatinine levels as an early indicator of AKI has limitations because of its slow rise and poor predictive accuracy for renal injury. This delay in diagnosis may lead to prolonged initiation in treatment and increased risk for adverse outcomes. OBJECTIVE: This pilot study explores serum and urine matrix metalloproteinases (MMPs)-2 and MMP-9 and their association, and potentially earlier detection of AKI in patients following cardiopulmonary bypass (CPB)-supported cardiac surgery. We hypothesize that increased activity of serum and urine levels MMP-2 and/ or MMP-9 are associated with AKI. Furthermore, MMP-2 and/ or MMP-9 may provide earlier identification of AKI as compared with serum levels of creatinine. METHODS: During the study period, there were 150 CPB-supported surgeries, 21 of which developed AKI according to the Kidney Disease Improving Global Outcomes criteria. We then selected a sample of 21 matched cases from those patients who went through the surgery without developing AKI. Primary outcomes were the measurement via gel zymography of the serum and urine activity of MMP-2 and MMP-9 drawn at the following intervals: pre-CPB; 10-minute post-CPB; and 4-hour post-CPB time points. Secondary variables were the measurement of serum creatinine, intensive care unit (ICU) fluid balance, and length of ICU stay. RESULTS: At the 10-minute and 4-hour post-CPB time points, the serum MMP-2 activity of AKI patients were significantly higher as compared with non-AKI patients (P < .001 and P = .004), respectively. Similarly, at the 10-minute and 4-hour post-CPB time points, the serum MMP-9 activity of AKI patients was significantly higher as compared with non-AKI patients (P = .001 and P = .014), respectively. The activity of urine MMP-2 and MMP-9 of AKI patients was significantly higher as compared with non-AKI patients at all 3 time points (P = .004, P < .001, P < .001), respectively. CONCLUSION: Although the pilot study may have limitations, it has demonstrated that the serum and urine levels of activity of MMP-2 and MMP-9 are associated with the clinical endpoint of AKI and appear to have earlier rising levels as compared with those of serum creatinine. Furthermore, in depth, exploration is underway with a larger sample size to attempt validation of the analytical performance and reproducibility of the assay for MMP-2 and MMP-9 to aid in earlier diagnosis of AKI following CPB-supported cardiac surgery.

CONTEXTE: L'insuffisance rénale aiguë (IRA) associée à la chirurgie cardiaque est un effet indésirable qui augmente la morbidité et la mortalité des patients qui subissent ce type d'intervention. La mesure de la créatinine sérique comme indicateur précoce de l'IRA continue à ce jour de présenter des limites en raison de sa lente augmentation et de l'imprécision de son pouvoir prédictif. Ce délai dans le diagnostic peut retarder l'initiation du traitement et accroître le risque d'effets indésirables. OBJECTIFS: Cette étude pilote explore les métalloprotéinases matricielles (MPM) -2 et -9 sériques et urinaires, leur association avec l'IRA et leur potentiel pour la détection plus précoce de la maladie chez les patients qui subissent une chirurgie cardiaque assistée par circulation extracorporelle. Nous émettons l'hypothèse qu'une hausse de l'activité des MMP-2 et/ou -9 et de leurs taux sériques et urinaires serait associée à l'IRA. Les MMP-2 et/ou -9 pourraient en outre permettre d'identifier la maladie plus précocement que le taux de créatinine sérique. MÉTHODOLOGIE: Au cours de la période de l'étude, 150 chirurgies cardiaques assistées par circulation extracorporelle ont été effectuées et 21 ont été associées à une IRA telle que définie par les critères du KDIGO (Kidney Disease Improving Global Outcomes). Nous avons sélectionné 21 cas appariés parmi les patients ayant subi l'intervention sans développer d'IRA. Le principal critère d'évaluation était une mesure de l'activité des MMP-2 et -9 obtenue par une zymographie sur gel d'échantillons de sérum et d'urine prélevés aux intervalles suivants: pré-circulation extracorporelle, 10 minutes après la circulation extracorporelle et 4 heures après la circulation extracorporelle. Les variables secondaires étaient la mesure de la créatinine sérique, la mesure de la balance liquidienne durant le séjour à l'unité de soins intensifs (USI) et de la durée du séjour à l'USI. RÉSULTATS: L'activité des MMP-2 sériques des patients atteints d'IRA était significativement plus élevée que celle des patients non atteints d'IRA 10 minutes et 4 heures post-circulation extracorporelle (p < 0,001 et p = 0,004 respectivement). Aux mêmes repères temporels, l'activité des MMP-9 sériques était elle aussi significativement plus élevée chez les patients atteints d'IRA (p = 0,001 [IRA]; p = 0,014 (non IRA). L'activité des MMP-2 et -9 urinaires, elle était elle aussi significativement plus élevée pour les patients atteints d'IRA, et ce, pour les trois points temporels (p = 0,004 [IRA); p < 0,001 [non IRA]). CONCLUSION: Bien que cette étude pilote comporte des limites, elle a tout de même démontré que l'activité des MMP-2 et -9 sériques et urinaires est associée aux paramètres cliniques de l'IRA, et que leurs taux augmentent plus rapidement que les taux de créatinine sérique. Des recherches plus approfondies sur un plus grand échantillon de patients sont en cours afin de valider la performance analytique et la reproductibilité du dosage des MMP-2 et -9 pour diagnostiquer plus rapidement l'IRA après une chirurgie cardiaque assistée par circulation extracorporelle.

Recombinant Factor VIII Measurement in a Hemophilia A Patient Undergoing Cardiopulmonary Bypass-Supported Cardiac Surgery.

Patients with hemophilia A (Hem A) requiring cardiopulmonary bypass-supported cardiac surgery pose unique challenges for perioperative hemostatic management. This report describes a staged perioperative approach to clinical hematologic management as applied to an 80-year-old male of O-positive blood type with mild Hem A, who underwent successful, uncomplicated coronary artery bypass graft surgery. Hematologic management primarily consisted of normalization of plasma factor VIII levels followed by standard care. Conventional laboratory methods and point-of-care-testing methods such as thromboelastography and heparin management assays were combined to guide patient care. Minimal blood loss and minimal hemodilution techniques were also used to achieve favorable outcomes. The thorough preparation and execution of care by our multidisciplinary team from perfusion, pathology and laboratory medicine, cardiovascular surgery, transfusion services, nursing, and anesthesia, facilitated a safe, smooth, clinical course and an optimal outcome.

Factor V Leiden and Cardiopulmonary Bypass.

We present a case of a patient with factor V Leiden with an antithrombin III activity of 67% who received a successful aortic valve replacement supported by cardiopulmonary bypass (CPB). A safe level of anticoagulation was achieved by monitoring activated clotting time (ACT) and heparin concentration ensuring adequate anticoagulation throughout the procedure. Results from ACT, heparin dose response, heparin protamine titration, and thrombelastography are given. Factor V Leiden patients can be safely anti-coagulated using heparin for CPB procedures when monitored with ACT, heparin protamine titration, and thrombelastography. Postoperative chest tube losses were 360 mL, less than half our institutional average. Anticoagulation for the pre-and post-operative phase is also discussed.