Safi Dokmak

The sensing of poorly deformable red blood cells by the human spleen can be mimicked in vitro

Retention of poorly deformable red blood cells (RBCs) by the human spleen has been recognized as a critical determinant of pathogenesis in hereditary spherocytosis, malaria, and other RBC disorders. Using an ex vivo perfusion system, we had previously shown that retention of Plasmodium falciparum-infected RBCs (Pf-RBCs) occur in the splenic red pulp, upstream from the sinus wall. To experimentally replicate the mechanical sensing of RBCs by the splenic microcirculation, we designed a sorting device where a mixture of 5- to 25-μm-diameter microbeads mimics the geometry of narrow and short interendothelial splenic slits. Heated RBCs, Pf-RBCs, and RBCs from patients with hereditary spherocytosis were retained in the microbead layer, without hemolysis. The retention rates of Pf-RBCs were similar in microbeads and in isolated perfused human spleens. These in vitro results directly confirm the importance of the mechanical sensing of RBCs by the human spleen. In addition, rigid and deformable RBC subpopulations could be separated and characterized at the molecular level, and the device was used to deplete a stored RBC population from its subpopulation of rigid RBCs. This experimental approach may contribute to a better understanding of the role of the spleen in the pathogenesis of inherited and acquired RBC disorders.

Surface Area Loss and Increased Sphericity Account for the Splenic Entrapment of Subpopulations of Plasmodium falciparum Ring-Infected Erythrocytes

Ex vivo perfusion of human spleens revealed innate retention of numerous cultured Plasmodium falciparum ring-infected red blood cells (ring-iRBCs). Ring-iRBC retention was confirmed by a microsphiltration device, a microbead-based technology that mimics the mechanical filtering function of the human spleen. However, the cellular alterations underpinning this retention remain unclear. Here, we use ImageStream technology to analyze infected RBCs’ morphology and cell dimensions before and after fractionation with microsphiltration. Compared to fresh normal RBCs, the mean cell membrane surface area loss of trophozoite-iRBCs, ring-iRBCs and uninfected co-cultured RBCs (uRBCs) was 14.2% (range: 8.3–21.9%), 9.6% (7.3–12.2%) and 3.7% (0–8.4), respectively. Microsphilters retained 100%, ∼50% and 4% of trophozoite-iRBCs, ring-iRBCs and uRBCs, respectively. Retained ring-iRBCs display reduced surface area values (estimated mean, range: 17%, 15–18%), similar to the previously shown threshold of surface-deficient RBCs retention in the human spleen (surface area loss: >18%). By contrast, ring-iRBCs that successfully traversed microsphilters had minimal surface area loss and normal sphericity, suggesting that these parameters are determinants of their retention. To confirm this hypothesis, fresh normal RBCs were exposed to lysophosphatidylcholine to induce a controlled loss of surface area. This resulted in a dose-dependent retention in microsphilters, with complete retention occurring for RBCs displaying >14% surface area loss. Taken together, these data demonstrate that surface area loss and resultant increased sphericity drive ring-iRBC retention in microsphilters, and contribute to splenic entrapment of a subpopulation of ring-iRBCs. These findings trigger more interest in malaria research fields, including modeling of infection kinetics, estimation of parasite load, and analysis of risk factors for severe clinical forms. The determination of the threshold of splenic retention of ring-iRBCs has significant implications for diagnosis (spleen functionality) and drug treatment (screening of adjuvant therapy targeting ring-iRBCs).

Benefit of initial resection of hepatocellular carcinoma followed by transplantation in case of recurrence: An intention‐to‐treat analysis

Liver resection (LR) for hepatocellular carcinoma (HCC) as the first‐line treatment in transplantable patients followed by “salvage transplantation” (ST) in case of recurrence is an attractive concept. The aim was to identify patients who gain benefit from this approach in an intention‐to‐treat study. From 1998 to 2008, among 329 potential candidates for liver transplantation (LT) with HCC within the Milan criteria (MC), 138 with good liver function were resected (LR group) from a perspective of ST in case of recurrence, and 191 were listed for LT first (LT group). The two groups were compared on an intention‐to‐treat basis with special reference to management of recurrences and transplantability after LR. Univariate and multivariate analyses were performed to identify resected patients who developed recurrence beyond MC. Five‐year overall and disease‐free survival was similar in both groups: LT versus LR group, 60% versus 77% and 56% versus 40%, respectively. Among the 138 patients in the LR group, 20 underwent LT before recurrence, 39 (28%) had ST, and 51 (37%) with recurrence were not transplanted including 21 within MC who were excluded for advanced age, acquired comorbidities, or refusal and 30 (22%) with recurrence beyond MC. Predictive factors for nontransplantability due to recurrence beyond MC included microscopic vascular invasion (hazard ratio [HR] 2.38 [range, 1.10‐7.29]), satellite nodules (HR 2.46 [range, 1.01‐6.68]), tumor size > 3 cm (HR 1.34 [range, 1.03‐3.12]), poorly differentiated tumor (HR 3.18 [range, 1.31‐7.70]), and liver cirrhosis (HR 1.90 [range, 1.04‐3.12]). Conclusion: The high risk of failure of ST after initial LR for HCC within MC suggests the use of tissue analysis as a selection criterion. The salvage LT strategy should be restricted to patients with favorable oncological factors. (HEPATOLOGY 2012;;55:132–140)

Prognostic value of muscle atrophy in cirrhosis using psoas muscle thickness on computed tomography.

BACKGROUND & AIMS Waiting-list mortality in patients with cirrhosis and a relatively low MELD score is a matter of concern. The aim of this study was to determine whether a marker of muscle waste could improve prognostication. METHODS A pre-MELD cohort (waiting time-based allocation; n=186) and a MELD-era cohort (n=376) were examined. At evaluation, transversal psoas muscle thickness (TPMT) was measured on a computed tomography (CT) image at the level of the umbilicus. In the pre-MELD cohort, TPMT/height (mm/m) and the MELD score were entered in univariate and multivariate models to predict mortality after registration. Applicability of pre-MELD findings was tested in the MELD-era. RESULTS In the pre-MELD cohort, the MELD score and TPMT/height were significantly associated with mortality. The discrimination of a score combining MELD and TPMT/height (MELD-psoas) was 0.84 (95% CI, 0.62-0.95). In the MELD-era, TPTM/height was significantly associated with mortality, independent of the MELD and MELD-Na scores. There was a 15% increase in mortality risk per unit decrease in TPMT/height. The discrimination of MELD-psoas score (0.82; 95% CI, 0.64-0.93) was superior to that of the MELD score and similar to that of the MELD-Na score. In patients with refractory ascites, mortality was significantly higher when TPMT/height was <16.8 mm/m (42% vs. 9%, p=0.02). CONCLUSIONS TPMP/height on CT at the level of the umbilicus, an objective marker of muscle waste, may be predictive of mortality in cirrhotic patients, independent of the MELD and MELD-Na scores. It may help to better assess the prognosis of patients with refractory ascites.

Ischemic Complications After Pancreaticoduodenectomy: Incidence, Prevention, and Management

Objective:To assess prevalence, prevention, and management strategy of visceral ischemic complications after pancreaticoduodenectomy (PD). Background:Ischemic complications after PD resulting from preexisting celiac axis (CA), superior mesenteric artery (SMA), stenosis, or intraoperative arterial trauma appear as an underestimated cause of death. Their prevention and adequate management are challenging. Methods:From 1995 to 2006, 545 PD were performed in our institution. All patients were evaluated by thin section multidetector computed tomography (CT) with arterial reconstruction to detect and class SMA or CA stenosis. Hemodynamical significance of stenosis was assessed preoperatively by arteriography for atherosclerotic stenosis and intraoperatively by gastroduodenal artery clamping test for CA compression by median arcuate ligament. Significant atherosclerotic stenosis was stented or bypassed, whereas CA compression was treated by median arcuate ligament division during PD. Multidetector-CT accuracy to detect arterial stenosis, results of revascularization procedures, and both prevalence and prognosis of ischemic complications after PD were analyzed. Results:Among 62 (11%) stenoses detected by multidetector-CT, 27 (5%) were hemodynamically significant, including 23 CA compressions by median arcuate ligament, 2 CA, and 2 SMA atherosclerotic stenoses, respectively. All atherosclerotic stenoses were successfully treated by preoperative stenting (n = 3) or bypass (n = 1). Among the 23 cases who underwent median arcuate ligament division, 3 (13%) failed due to 1 CA injury and 2 misdiagnosed intrinsic CA stenoses. Overall, 6 patients developed ischemic complications, due to intraoperative hepatic artery injury (n = 4), unrecognized SMA atherosclerotic stenosis (n = 1), or CA fibromuscular dysplasia (n = 1). Five (83%) of them died, representing 36% of the 14 deaths of the whole series (overall mortality = 2.6%). Overall, CT detected significant arterial stenosis with a 96% sensitivity and determined etiology of CA stenosis with a 92% accuracy. Conclusions:Ischemic complications are an underestimated cause of death after PD and are due to preexisting stenoses of CA and SMA, or intraoperative hepatic artery injury. Preexisting arterial stenoses are detected by routine multidetector CT. Preoperative endovascular stenting for intrinsic stenosis, division of median arcuate ligament for extrinsic compression, and meticulous dissection of the hepatic artery can contribute to minimize ischemic complications.

Changes in Tumor Density in Patients with Advanced Hepatocellular Carcinoma Treated with Sunitinib

Purpose: Response Evaluation Criteria in Solid Tumors (RECIST) may underestimate the efficacy of targeted therapies. In hepatocellular carcinoma (HCC) studies with sunitinib, RECIST-defined response rates are low, although hypodensity on computed tomography (CT) scans occurs more frequently. This exploratory analysis investigated tumor density as a surrogate endpoint of sunitinib activity in a phase II HCC study. Experimental Design: Patients received sunitinib 50 mg/d (4 weeks on/2 weeks off). Tumor size and density were assessed on CT scans by using RECIST and Choi criteria, the latter of which classify a partial response as a 15% or more reduction in tumor density or a 10% or more reduction in tumor size. The overall percentage volume of tumor necrosis was calculated with volumetric reconstruction. Tumor perfusion parameters were assessed by using perfusion CT scans with specific acquisition. Results: Among the 26 evaluable patients, 1 achieved a partial response and 22 had tumor stabilization by RECIST. In analysis of tumor density, 17 of 26 patients (65.4%) were responders by Choi criteria. Volumetric assessment showed major tumor necrosis (≥30% of tumor volume) in 10 of 21 patients (47.6%). Among four patients evaluated, tumor blood flow was reduced by 58.8% and blood volume by 68.4% after 4 weeks of treatment. The median time to progression (TTP) was 6.4 months. Patients with responses by Choi criteria had a significantly longer TTP (7.5 months) compared with nonresponders (4.8 months; HR = 0.33, two-sided P = 0.0182). Conclusions: Tumor density assessment suggested that radiologic endpoints in addition to RECIST may be considered to capture sunitinib activity in HCC. Clin Cancer Res; 17(13); 4504–12. ©2011 AACR.

Laparoscopic resection of hepatocellular carcinoma: a French survey in 351 patients.

OBJECTIVES Current clinical studies report the results of laparoscopic resection of hepatocellular carcinoma (HCC) obtained in small cohorts of patients. Because France was involved in the very early development of laparoscopic surgery, the present study was conducted in order to report the results of a large, multicentre experience. METHODS A total of 351 patients underwent laparoscopic liver resection for HCC during the period from 1998 to 2010 in nine French tertiary centres. Patient characteristics, postoperative mortality and morbidity, and longterm survival were retrospectively reviewed. RESULTS Overall, 85% of the study patients had underlying liver disease. Types of resection included wedge resection (41%), left lateral sectionectomy (27%), segmentectomy (24%), and major hepatectomy (11%). Median operative time was 180 min. Conversion to laparotomy occurred in 13% of surgeries and intraoperative blood transfusion was necessary in 5% of patients. The overall morbidity rate was 22%. The 30-day postoperative mortality rate was 2%. Negative resection (R0) margins were achieved in 92% of patients. Rates of overall and progression-free survival at 1, 3 and 5 years were 90.3%, 70.1% and 65.9%, and 85.2%, 55.9% and 40.4%, respectively. CONCLUSIONS This multicentre, large-cohort study confirms that laparoscopic liver resection for HCC is a safe and efficient approach to treatment and can be proposed as a first-line treatment in patients with resectable HCC.

Which limits to the "ALPPS" approach?

W e read with much interest the article written by Schnitzbauer and coworkers.1 This technique undoubtedly represents a breakthrough in the field of hepatobiliary surgery. Yet, like every new advance, several aspects require further discussion. Accordingly, we believe that our own experience in 8 patients who underwent a similar procedure during the past year, allows us to confirm some important results and share some additional ones. In this article, the authors describe a strategy in which biliary structures are preserved. In such context, they emphasize the outstanding 74% increase of the future liver remnant volume. In our patients, we have adopted a different approach and have systematically performed associated right bile duct ligation to further enhance future liver remnant regeneration. Indeed, bile duct obstruction is believed to induce atrophy of the nondrained liver and trigger compensatory controlateral hypertrophy of the future liver remnant. In these patients, the 70% (5–147) future liver remnant hypertrophy rate observed on postoperative day 7 was similar to that observed in the present study. Yet, our patients experienced a high 87.5% rate of biliary fistula and biloma originating from the cut surface on the ligated duct. Considering that the occurrence of such a complication could contribute to both impairing future liver remnant regeneration and increasing the rate of adhesions or postoperative complications, we recommend not to routinely perform bile duct ligation. The correlation between liver volume and function, which is a matter of ongoing investigation, will need to be more thoroughly discussed. In the present study, liver regeneration was considered on a volumetric basis alone. In our experience, however, 2 patients with mild (<40%) volumetric future liver remnant hypertrophy experienced postoperative liver failure and prolonged (>3 months) jaundice. The first one underwent right trisectionectomy for colorectal liver metastases after 18 cycles of induction chemotherapy and pathological analysis of the resected specimen which revealed severe sinusoidal obstruction

Laparoscopic Pancreaticoduodenectomy Should Not Be Routine for Resection of Periampullary Tumors

BACKGROUND Laparoscopic pancreaticoduodenectomy (LPD) is a difficult procedure that has become increasingly popular. Nevertheless, comparative data on outcomes remain limited. Our aim was to compare the outcomes of LPD and open pancreaticoduodenectomy (OPD). STUDY DESIGN Between April 2011 and April 2014, 46 LPD were performed and compared with 46 OPD, which theoretically can be done by the laparoscopic approach. Patients were also matched for demographic data, associated comorbidities, and underlying disease. Patient demographics and perioperative and postoperative outcomes were studied from our single center prospective database. RESULTS Lower BMI (23 vs 27 kg/m(2), p < 0.001) and a soft pancreas (57% vs 47%, p = 0.38) were observed in patients with LPD, but there were no differences in associated comorbidities or underlying disease. Surgery lasted longer in the LPD group (342 vs 264 minutes, p < 0.001). One death occurred in the LPD group (2.1% vs 0%, p = 0.28) and severe morbidity was higher (28% vs 20%, p = 0.32) in LPD due to grade C pancreatic fistula (PF) (24% vs 6%, p = 0.007), bleeding (24% vs 7%, p = 0.02), and revision surgery (24% vs 11%, p = 0.09). Pathologic examination for malignant diseases did not identify any differences between the LPD and OPD as far as size (2.51 vs 2.82 cm, p = 0.27), number of harvested (20 vs 23, p = 0.62) or invaded (2.4 vs 2, p = 0.22) lymph nodes, or R0 resection (80% vs 80%; p = 1). Hospital stays were similar (25 vs 23 days, p = 0.59). There was no difference in outcomes between approaches in patients at a lower risk of PF. CONCLUSIONS This study found that LPD is associated with higher morbidity, mainly due to more severe PF. Laparoscopic pancreaticoduodenectomy should be considered only in the subgroup of patients with a low risk of PF.

Preoperative CT scan helps to predict the occurrence of severe pancreatic fistula after pancreaticoduodenectomy.

Objective: To assess the influence of body fat distribution, estimated by a preoperative computed tomographic (CT) scan, on pancreatic fistula (PF) risk after pancreaticoduodenectomy (PD). Background: Pancreatic fatty infiltration is a predictive factor of PF, but accurate preoperative assessment is challenging. We hypothesized that it could be associated with an increased visceral obesity and could be assessed preoperatively. Methods: Over 18 months, 103 consecutive patients with PD and pancreaticogastrostomy were studied. Demographic, radiologic, and pathologic data were correlated to PF occurrence. Radiologic data included on a nonenhanced CT acquisition: pancreas, spleen, and liver density measures (Dpancreas, Dspleen, and Dliver [densities of the pancreas, spleen, and liver in hounsfield units], respectively), retro-renal fat thickness, and at the level of the umbilicus, total, visceral, and subcutaneous fat area (TFA [total fat area], VFA [visceral fat area], and SFA [subcutaneous fat area], respectively). Pancreatic fatty infiltration was graded histologically. Logistic regression analysis was used to identify independent predictors of PF-graded B and C according to the International Study Group on the Pancreatic Fistula. Results: Among the 103 patients, 37% (n = 38) developed a PF (47.4% grade A, 39.5% grade B, and 13.1% grade C). PF risk was correlated with pancreatic fatty infiltration (P = 0.017). In univariate analysis, male gender (P = 0.023), body mass index (BMI) over 25 kg/m2 (P = 0.02), retro-renal fat thickness over 15 mm (P = 0.006), TFA over the median (>233 cm2; P = 0.023), and VFA over the median (>84 cm2; P < 0.0001) were significantly associated with an increased risk of symptomatic PF (grade B and C). In multivariate analysis, VFA greater than 84 cm2 (OR = 8.16, P = 0.002) was the only independent predictive factor of grade B or C PF. Using the same model, a VFA greater than 84 cm2 was the only independent factor associated with the presence of fatty pancreas on pathologic examination. Conclusions: Preoperative assessment of body fat distribution by a CT scan, as a surrogate for fatty pancreas infiltration, can help to predict the occurrence of clinically significant PF after PD.