Vassilios Smyrniotis

Vascular control during hepatectomy : Review of methods and results

The various techniques of hepatic vascular control are presented, focusing on the indications and drawbacks of each. Retrospective and prospective clinical studies highlight aspects of the pathophysiology, indications, and morbidity of the various techniques of hepatic vascular control. Newer perspectives on the field emerge from the introduction of ischemic preconditioning and laparoscopic hepatectomy. A literature review based on computer searches in Index Medicus and PubMed focuses mainly on prospective studies comparing techniques and large retrospective ones. All methods of hepatic vascular control can be applied with minimal mortality by experienced surgeons and are effective for controlling bleeding. The Pringle maneuver is the oldest and simplest of these methods and is still favored by many surgeons. Intermittent application of the Pringle maneuver and hemihepatic occlusion or inflow occlusion with extraparenchymal control of major hepatic veins is particularly indicated for patients with abnormal parenchyma. Total hepatic vascular exclusion is associated with considerable morbidity and hemodynamic intolerance in 10% to 20% of patients. It is absolutely indicated only when extensive reconstruction of the inferior vena cava (IVC) is warranted. Major hepatic veins/ and limited IVC reconstruction has been also achieved under inflow occlusion with extraparenchymal control of major hepatic veins or even using the intermittent Pringle maneuver. Ischemic preconditioning is strongly recommended for patients younger than 60 years and those with steatotic livers. Each hepatic vascular control technique has its place in liver surgery, depending on tumor location, underlying liver disease, patient cardiovascular status, and, most important, the experience of the surgical and anesthesia team.

Selective Hepatic Vascular Exclusion versus Pringle Maneuver in Major Liver Resections: Prospective Study

Selective hepatic vascular exclusion (SHVE) and the Pringle maneuver are two methods used to control bleeding during hepatectomy. They are compared in a prospective randomized study, where 110 patients undergoing major liver resection were randomly allocated to the SHVE group or the Pringle group. Data regarding the intraoperative and postoperative courses of the patients are analyzed. Intraoperative blood loss and transfusion requirements were significantly decreased in the SHVE group, and postoperative liver function was better in that group. Although there was no difference between the two groups regarding the postoperative complications rate, patients offered the Pringle maneuver had a significantly longer hospital stay. The application of SHVE did not prolong the warm ischemia time or the total operating time. It is evident from the present study that SHVE performed by experienced surgeons is as safe as the Pringle maneuver and is well tolerated by the patients. It is much more effective than the Pringle maneuver for controlling intraoperative bleeding, and it is associated with better postoperative liver function and shorter hospital stay.

Hemodynamic interaction between portal vein and hepatic artery flow in small-for-size split liver transplantation.

Abstract.In split-liver transplantation, the entire portal flow is redirected through relatively small-for-size grafts. It has been postulated that excessive portal blood flow leads to graft injury. In order to elucidate the mechanisms of this injury, we studied the hemodynamic interactions between portal vein- and hepatic artery flow in an experimental model in pigs. Six whole pig liver grafts were implanted in Group 1 (n=6) and six whole liver grafts were split into right and left grafts and transplanted to Groups 2 (n=6) and 3 (n=6), respectively. The graft-to-recipient liver volume ratio was 1:1, 2:3 and 1:3 in Groups 1, 2 and 3, respectively. Portal vein- and hepatic artery flows were measured with an ultrasonic flow meter at 60,120 and 180min after graft reperfusion. Portal vein pressure was also recorded at the same time intervals. Graft function was assessed at 3,6h and 12h, and morphological changes at 12h after reperfusion. Following reperfusion, portal vein flow showed an inverse relationship to graft size, while hepatic artery flow was reduced proportionately to graft size. The difference was significant among the three groups (P<0.05). Portal vein pressure was significantly higher in group 3, compared to groups 1 and 2 (P<0.05). Hepatic artery buffer response was significantly higher in Group 3, compared to Groups 1 and 2 in relation to pre-occlusion values (P<0.05). Split-liver transplantation, when resulting in small-for-size grafts, is associated with portal hypertension, diminished arterial flow, and graft dysfunction. Arterial flow impairment appears to be related to increased portal vein flow.

Total versus selective hepatic vascular exclusion in major liver resections

BACKGROUND Total hepatic vascular exclusion (THVE) and selective hepatic vascular exclusion (SHVE) are two effective techniques for bleeding control in major hepatic resections. Outcomes of the two procedures were compared. METHODS Patients undergoing major liver resection were randomly allocated to the THVE and SHVE groups. Intraoperative hemodynamic changes and the postoperative course of the two groups were compared. RESULTS During vascular clamping, the THVE group showed a significant elevation in pulmonary vascular resistance, systemic vascular resistance, intrapulmonary shunts, and a significant reduction in cardiac index, compared with the SHVE group (P <0.05). Patients undergoing THVE received more crystalloids and blood, showed more severe liver, renal and pancreatic dysfunction, and had a longer hospital stay than the SHVE group (P <0.05). CONCLUSIONS Both techniques are equally effective in bleeding control in major liver resections. THVE is associated with cardiorespiratory and hemodynamic alterations and may be not tolerated by some patients. SHVE is well tolerated with fewer postoperative complications and shorter hospitalization time.

Anesthetic and perioperative management of adult transplant recipients in nontransplant surgery.

E ach year, .16,000 patients receive whole organ transplants in the United States alone, and this number is expected to increase yearly (1). Because the 1-yr survival rate for most transplant recipients is approaching 80%–90% and continues to improve annually, an increasing number of patients who received a transplant present for either elective or emergency nontransplant surgery (2–4). Therefore, anesthesiologists and surgeons are often required to manage transplant recipients in hospitals that are not otherwise involved in transplantation procedures. The general considerations related to any transplant recipient are the physiological and pharmacological problems of allograft denervation, the side effects of immunosuppression, the risk of infection, and the potential for rejection.

Long-Term Management of Noncancer Pain With Transdermal Therapeutic System-Fentanyl

Transdermal therapeutic system-fentanyl (TTS-F) has been extensively studied in cancer pain management. However, few studies have addressed the long-term management of noncancer pain, especially when it relates to neuropathic pain. A total of 529 patients were recruited into this prospective open-label study to determine the safety and effectiveness of TTS-F in relation to quality-of-life (QOL) stratified according to pain type and etiology. TTS-F significantly improves QOL within 28 days, and pain management within 48 hours. The frequency of side effects rapidly decreases over time, and patients not experiencing adequate pain management are identified within 28 days. The median duration of therapy for effective pain management was 10 months, and 90% of patients sustained such efficacy. TTS-F offers statistically significant increases in QOL-Short Form 12 (including the Physical Component Scale and Mental Component Scale measures) and pain control (Greek Brief Pain Inventory) from one time point to the next (P <.0001). These improvements are not influenced by pain type or etiology. TTS-F is a safe and effective pain management system independent of patient characteristics and demographic factors. What is of most importance is that in those patients with neuropathic pain, for whom opioids have long been thought to be ineffective, similar effectiveness is demonstrated when compared to patients with nociceptive pain.

Global Consequences of Liver Ischemia/Reperfusion Injury

Liver ischemia/reperfusion injury has been extensively studied during the last decades and has been implicated in the pathophysiology of many clinical entities following hepatic surgery and transplantation. Apart from its pivotal role in the pathogenesis of the organs post reperfusion injury, it has also been proposed as an underlying mechanism responsible for the dysfunction and injury of other organs as well. It seems that liver ischemia and reperfusion represent an event with “global” consequences that influence the function of many remote organs including the lung, kidney, intestine, pancreas, adrenals, and myocardium among others. The molecular and clinical manifestation of these remote organs injury may lead to the multiple organ dysfunction syndrome, frequently encountered in these patients. Remote organ injury seems to be in part the result of the oxidative burst and the inflammatory response following reperfusion. The present paper aims to review the existing literature regarding the proposed mechanisms of remote organ injury after liver ischemia and reperfusion.

Pathways and targets in hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) has been rising in several western low-incidence areas over the past decade. The purpose of this review was to summarize the current knowledge on the ‘state of the art’ management of HCC focusing on targeted systemic therapies. The information for this review was compiled by searching the PubMed and MEDLINE databases for articles published until 1 June 2012. Cytotoxic chemotherapy has failed to affect outcome of HCC. Treatment with sorafenib is associated with survival gain in HCC but the responses are not durable. In addition, sorafenib is associated with substantial dermatologic and gastrointestinal toxicity. In this review, the authors summarize molecular targets and signal transduction pathways in HCC and provide an update of published and ongoing studies. Many targeted agents against angiogenesis, Ras/Raf/MAPK, EGF receptor, PI3K/AKT/mTOR, HGF/Met and IGF/IGF receptor are being tested in clinical trials.

Ischemia/reperfusion injury in liver resection: a review of preconditioning methods.

Ischemic preconditioning is one of the therapeutic interventions aiming at preventing ischemia/reperfusionrelated injury. Numerous experimental studies and a few clinical series have shown that during liver resections, ischemic preconditioning is a promising strategy for optimizing the postoperative outcome. Moreover, various types of pharmacological intervention as well as different types of preconditioning, such as remote preconditioning, the use of heat shock, and hyperbaric oxygen, have been developed to attenuate the functional impairment accompanying ischemia/reperfusion injury. This review summarizes the various forms of preconditioning, thus suggesting that close cooperation between surgeons and anesthesiologists paves the way to apply novel strategies to improve the outcome of liver resection.

Cystic pancreatic neoplasms: computed tomography and magnetic resonance imaging findings.

SummaryCystic pancreatic neoplasms include serous cystadenomas (SCA), mucin-producing cystic tumors, cystic islet-cell tumors, and cystic solid and papillary epithelial neoplasms. Imaging techniques are of great value in the demonstration and differential diagnosis of these tumors. In this article we present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of the aforementioned cystic neoplasms. Although the radiological features are in many cases informative, a significant overlap does exist; fineneedle aspiration biopsy and cytology or excisional biopsy and histological examination are necessary to determine a definitive diagnosis.