A Canadian Provincial Screening Program for Lynch Syndrome.

INTRODUCTION: Manitoba implemented the first Canadian provincial program of reflex screening through mismatch repair immunohistochemistry (MMR-IHC) for all colorectal cancers diagnosed at age 70 years or younger in December 2017. We evaluated compliance to universal reflex testing and for referrals to Genetics for individuals with MMR-deficient tumors. METHODS: We searched the provincial pathology database with "adenocarcinoma" in the colorectal specimen pathology reports between March 2018 and December 2020. We cross-referenced with paper and electronic records in the Program of Genetics and Metabolism to determine whether patients with MMR-deficient tumors had been referred for Genetic assessment and what proportion of patients and first-degree relatives accepted an appointment and genetic testing. We performed logistic regression analysis to identify predictors of testing. RESULTS: We identified 3,146 colorectal adenocarcinoma specimens (biopsies and surgical resections) from 1,692 unique individuals (mean age 68.66 years, male 57%). Of those aged 70 years or younger (n = 936), 89.4% received MMR-IHC screening. Individual pathologists (categorized by the highest, average, and lowest screening rates) were the biggest predictors of MMR-IHC screening on multivariable analysis (highest vs lowest: odds ratio 17.5, 95% confidence interval 6.05-50.67). While only 53.4% (n = 31) of 58 screen-positive cases were referred by pathologists for genetic assessment, other clinicians referred an additional 22.4% (n = 13), resulting in 75.8% overall referral rate of screen-positive cases. Thirteen (1.4%) patients (1.1%, aged 70 years or younger) were confirmed to experience Lynch syndrome through germline testing, and 8 first-degree relatives (an average of 1.6 per patient) underwent cascade genetic testing. DISCUSSION: The first Canadian Lynch syndrome screening program has achieved high rates of reflex testing.

Adiponectin deficiency induces hepatic steatosis during pregnancy and gestational diabetes in mice.

AIMS/HYPOTHESIS: Obesity and hepatic steatosis are risk factors for gestational diabetes mellitus (GDM), a common complication of pregnancy. Adiponectin is a fat-derived hormone that improves hepatic steatosis and insulin sensitivity. Low levels of circulating adiponectin are associated with GDM development. We hypothesised that adiponectin deficiency causes fatty liver during pregnancy, contributing to the development of GDM. METHODS: To determine the role of adiponectin in fatty liver development during pregnancy, we compared pregnant (third week of pregnancy) adiponectin knockout (KO) mice (strain B6;129-Adipoqtm1Chan/J) with wild-type mice and assessed several variables of hepatic lipid metabolism and glucose homeostasis. The impact of adiponectin supplementation was measured by administering adenovirus-mediated full-length adiponectin at the end of the second week of pregnancy and comparing with green fluorescent protein control. RESULTS: In the third week of pregnancy, fasted pregnant adiponectin KO mice were hyperglycaemic on a low-fat diet (9.2 mmol/l vs 7.7 mmol/l in controls, p<0.05) and were glucose and pyruvate intolerant relative to wild-type mice. Pregnant adiponectin KO mice developed hepatic steatosis and a threefold elevation in hepatic triacylglycerols (p<0.05) relative to wild-type mice. Gestational weight gain and food consumption were similar in KO and wild-type mice. Adenoviral-mediated adiponectin supplementation to pregnant adiponectin KO mice improved glucose tolerance, prevented fasting hyperglycaemia and attenuated fatty liver development. CONCLUSIONS/INTERPRETATION: Adiponectin deficiency increased hepatic lipid accumulation during the period of pregnancy associated with increased fat utilisation. Consequently, adiponectin deficiency contributed to glucose intolerance, dysregulated gluconeogenesis and hyperglycaemia, all of which are characteristic of GDM. Increasing adiponectin in the last week of pregnancy alleviated hepatic steatosis and restored normal glucose homeostasis during pregnancy.

Campylobacter concisus gastritis masquerading as Helicobacter pylori on gastric biopsy.

OBJECTIVE: Campylobacter concisus is a Gram-negative rod closely related to Helicobacter pylori. We sought to identify gastric biopsies positive for C. concisus that had been misdiagnosed as H. pylori gastritis in our routine surgical pathology practice. MATERIALS AND METHODS: We performed a retrospective review of gastric biopsies in our regional microbiology and pathology electronic records to identify cases that were submitted for H. pylori testing in which C. consicus was identified on culture and how many had concurrent biopsies sent to pathology for histologic assessment over a two-year period (2017-2018). Pathologic findings in the gastric biopsies were reviewed and immunohistochemical staining for H. pylori was performed. RESULTS: 50 of 2191 gastric biopsy specimens submitted to microbiology in 2017-18 grew C. concisus (2.3%), compared to 168 in which H. pylori was identified (7.7%). Twenty-eight cases had concurrent histology. A total of four cases (three from 2017 and one from 2018) demonstrated organisms morphologically identical to H. pylori in the H&E sections, of which all were H. pylori immunoreactive. CONCLUSIONS: Our case series is the first to demonstrate that C. concisus can mimic H. pylori gastritis in routine biopsy pathology.

Evidence of Hepatitis B Virus Infection in Cancer and Noncancer Stem Cells Associated with Human Hepatocellular Carcinoma.

Both the hepatitis B virus (HBV) and cancer stem cells (CSCs) have been independently implicated in the pathogenesis of hepatocellular carcinoma (HCC). To date, there have been no reports describing HBV infection within CSCs. In this report we describe HBV core (HBcAg) and HBx protein expression within CSCs associated with human HCC. HBV markers were also identified in nonmalignant stem cells present in adjacent nontumor tissue. These findings provide new insights into the pathogenesis of HBV-induced HCC and are potentially relevant to the treatment of both HCC and chronic HBV.

Maternal obesity characterized by gestational diabetes increases the susceptibility of rat offspring to hepatic steatosis via a disrupted liver metabolome.

Maternal obesity is associated with a high risk for gestational diabetes mellitus (GDM), which is a common complication of pregnancy. The influence of maternal obesity and GDM on the metabolic health of the offspring is poorly understood. We hypothesize that GDM associated with maternal obesity will cause obesity, insulin resistance and hepatic steatosis in the offspring. Female Sprague-Dawley rats were fed a high-fat (45%) and sucrose (HFS) diet to cause maternal obesity and GDM. Lean control pregnant rats received low-fat (LF; 10%) diets. To investigate the interaction between the prenatal environment and postnatal diets, rat offspring were assigned to LF or HFS diets for 12 weeks, and insulin sensitivity and hepatic steatosis were evaluated. Pregnant GDM dams exhibited excessive gestational weight gain, hyperinsulinaemia and hyperglycaemia. Offspring of GDM dams gained more weight than the offspring of lean dams due to excess adiposity. The offspring of GDM dams also developed hepatic steatosis and insulin resistance. The postnatal consumption of a LF diet did not protect offspring of GDM dams against these metabolic disorders. Analysis of the hepatic metabolome revealed increased diacylglycerol and reduced phosphatidylethanolamine in the offspring of GDM dams compared to offspring of lean dams. Consistent with altered lipid metabolism, the expression of CTP:phosphoethanolamine cytidylyltransferase, and peroxisomal proliferator activated receptor-α mRNA was reduced in the livers of GDM offspring. GDM exposure programs gene expression and hepatic metabolite levels and drives the development of hepatic steatosis and insulin resistance in young adult rat offspring.

The effect of total spinal anesthesia on cardiac function in a large animal model of brain death.

Brain death (BD) causes cardiac dysfunction in organ donors, attributable to the catecholamine storm that occurs with raised intracerebral pressure (ICP). However the direct contribution of the spinal sympathetics has not been well described. We examined the effect of total spinal anesthesia (TSA) on cardiac function in a large animal model of BD. Eighteen pigs were allocated to 3 experimental groups: Group 1, the saline-treated control group; Group 2, TSA administered prior to BD; and Group 3, TSA administered 30 min after BD. Inflation of an intracerebral balloon-tipped catheter was used to induce BD. Ventricular function was assessed using a pressure-volume loop catheter and magnetic resonance imaging. Serum catecholamine levels were assessed with high performance liquid chromatography. Inflation of the intracerebral balloon-tipped catheter was associated with a dramatic rise in heart rate and blood pressure, along with increased concentrations of serum epinephrine and norepinephrine. This phenomenon was not observed in Group 2. In Group 1, there was a significant decline in contractility, whereas groups 2 and 3 saw no change. Group 2 had greater contractile reserve than groups 1 and 3. Our data demonstrate the central role of spinal sympathetics in the hemodynamic response to raised ICP. Further work is required to determine the utility of TSA in reversing cardiac dysfunction in BD donors.

Spontaneous resolution of cystic adventitial disease: a word of caution.

Spontaneous resolution of cystic adventitial disease has been occasionally reported in the literature. It is unclear, however, whether this resolution is permanent. In this case report, we describe recurrence of a popliteal artery cystic adventitial disease after spontaneous resolution, which was successfully treated with surgery. The underlying mechanism is proposed. Without definitive treatment, the patients with spontaneous resolution of cystic adventitial disease may need long-term follow-up, given the risk of recurrence.

Cuspal dehiscence at a post and along the stent cloth in a bovine pericardium heart valve implanted for seven years.

A failing mitral valve prosthesis made from bovine pericardium was explanted from a 50-year-old patient. Preoperative transthoracic-echocardiography had confirmed severe mitral regurgitation due to structural failure of this HP Bio bovine pericardium heart valve prosthesis. The explanted device was examined macroscopically, by scanning electron microscopy (SEM), by light microscopy, and by transmission electron microscopy (TEM). Samples of unassembled patches of bovine pericardium were used as a pre-implantation control to better understand the changes that occurred in the structure of the pericardium following the 7 years of implantation. Examination confirmed complete dehiscence of a cusp along a valve post and the stent: This detached cusp was observed floating in the bloodstream at echocardiography. The fibrous pannus overgrowth was well developed along the stent and extended to the bottom of the cusps both on the inflow and the outflow sides. The fibrous panni were found to be poorly adhesive to the pericardium cusps and had become stiff, thus impairing the opening and closure of the valve. The structure of the pericardium cusps was severely deteriorated compared to the control bovine pericardium tissue samples. The collagen bundles were frequently broken and more stretched in the explanted device, lacking the wavy histological pattern of normal collagen fibers. However, the tissues were devoid of any calcification. In conclusion, the failure mode of this valve was the dehiscence of a cusp from a valve post and along the stent cloth in the absence calcification.

Can marine mammals be a reliable source for the manufacture of prosthetic heart valves for percutaneous surgery?

Marine mammals experience unique physiological conditions when diving. Myocardial function is sustained despite a 90% reduction of the blood flow in the coronaries. Therefore, their heart valves and pericardium could serve as a unique source of tissue for the manufacture of prosthetic heart valves. The pericardium of a stillborn pup sea lion was investigated to determine its morphology using gross observation, scanning electron microscopy (SEM), light microscopy, and transmission electron microscopy (TEM). Depending upon the site of sampling, the structure of the pericardium varied significantly. The atrial sample was well structured with wavy bundles of collagen fibers. The thickness in the atrial sample was regular with a smooth serous surface. The fibrous side of the pericardium of the auricular sample was irregular and incorporated microcapillaries. Both the sternoperitoneal ligament and the phrenoperitoneal ligament section were irregular and incorporated various amounts of adipocytes. Because of the increased amount of adipocytes, the fibrils of the collagen fibers were also observed to be occasionally agglutinated. Practically, the harvesting of pericardium would have to be restricted to the atrial surface. The presence of adipocytes in the pericardium wall makes the selection of this tissue a poor choice compared to alternative existing tissue sources.

Acute hepatitis as a manifestation of parvovirus B19 infection.

There are few reports in the literature of hepatitis as a manifestation of parvovirus B19 infection. We describe a case of parvovirus B19-associated acute hepatitis diagnosed based on a positive serologic test (IgM) and molecular detection of parvovirus B19 DNA in a liver biopsy specimen. Parvovirus B19 infection should be considered in the differential diagnosis of patients presenting with acute hepatitis.

Quality assurance review: Intra-operative evaluation of sentinel lymph nodes in breast cancer.

BACKGROUND: Intraoperative consultation (IOC) of axillary sentinel lymph node (SLN) biopsy continues to play a role in selected breast cancer patients. The reported sensitivity rates for intraoperative SLN evaluation in breast cancer range from 47% to 80%. We study a center where the majority of SLN IOC is performed by imprint cytology, and a protocol was established to limit microscopic examination to three slides for a reporting TAT goal of 30 min. METHODS: Approval to conduct this study was obtained from the REB. A retrospective review was performed on all consecutive SLN cases sent for IOC. Reported IOC assessments of all cases were compared with the final pathology. RESULTS: Of 164 patients, there were 22 (13%) false negative IOC events, including 15 missed macro-metastasis and 7 missed micro-metastasis. The overall sensitivity for touch imprint in detecting SLNs macro-metastasis was 70.9%. Reporting total turnaround time was on average 3 min longer, whereas sensitivity and specificity were not significantly different in the two protocol periods. CONCLUSION: Implementation of an IOC policy for a maximum of three slides for imprint cytology did not result in a significant impact on the sensitivity, specificity, or total turnaround time for SLN in breast cancer patients. False negative IOC events were mainly due to sampling error. Quality review was made difficult by limited documentation related to the gross handling of the specimens at IOC. System factors identified include insufficient space for the IOC report on the pathology requisition, and the lack of clearly communicated expectations for documentation.

Changes in liver biochemistry during methotrexate use for inflammatory bowel disease.

OBJECTIVES: We aimed to characterize the spectrum of liver enzyme test (LET) abnormalities that occur while using methotrexate for inflammatory bowel disease (IBD). METHODS: A retrospective review was undertaken of subjects using methotrexate for IBD at a single center. The clinical and epidemiological parameters, and hepatotoxicity risk factors, were recorded. Subjects were excluded if cumulative methotrexate doses could not be ascertained, if they had a diagnosis of rheumatoid arthritis or psoriasis, or if baseline and follow-up LETs were not available. Also noted were the cumulative methotrexate dose during the peak LET increase, severity of LET increase, and whether normalization occurred. RESULTS: Eighty-seven subjects were included (Crohn's disease, n=67; UC, n=17; indeterminate colitis n=3). The mean therapy duration was 81 weeks (3- to 364-week range), and the cumulative average dose was 1,813 mg (25-8,255-mg range). Thirty-seven (43%) subjects received a cumulative dose >1,500 mg. Sixty-seven (77%) had normal LETs, and in 51 (76%) LETs remained normal throughout methotrexate therapy. In the 16 (24%) who developed LET abnormalities, seven (44%) had underlying risk factor(s) for liver disease. Normalization (without dose reduction) occurred in 14 (88%) while continuing methotrexate. Of 20 subjects with abnormal LETs at baseline, nine (45%) subsequently normalized while continuing methotrexate, whereas nine (45%) worsened. Seventeen liver biopsies were performed in 11 and were classified as Roenigk's grade I in 15 (88%) subjects. Roenigk IIIb or IV was not seen. CONCLUSIONS: Methotrexate is commonly associated with LET abnormalities, but these frequently normalize while still on therapy, and in only 5% will drug discontinuation be necessary. Liver biopsies rarely have substantive abnormalities.

Hepatitis B Virus Infection of Normal Hepatic Stem/Progenitor Cells.

BACKGROUND/AIMS: Whether the hepatitis B virus (HBV) infects normal hepatic stem/progenitor cells (NSCs) and if so, whether such infections play a role in the pathogenesis of HBV-induced chronic liver disease (CLD) and/or hepatocellular carcinoma (HCC) remains to be determined. The objectives of this study were to determine whether HBV infects NSCs and whether such infections alter NSC activity in a manner likely to contribute to the development of CLD and/or HCC. METHODS: Liver biopsies from five hepatitis B surface antigen (HBsAg) positive patients were co-stained for HBcAg and HBx and the stem cell markers EpCAM, Oct-4 and Nanog. In addition, primary NSCs derived from healthy human livers were exposed to HBV contaminated serum in vitro. Supernatant and/or cellular HBsAg, HBcAg and HBV-DNA expression were documented over the subsequent 30 days of culture. Pro- and anti-inflammatory cytokine expression, membrane potential differences (PDs), proliferative and telomerase activities of HBV-infected NSCs were also documented. RESULTS: Markers of HBV infection were present within the NSC population of all five biopsy specimens. In vitro, HBV markers appeared within three days of exposure, peaked in expression after 10-15 days and remained positive thereafter for the duration of cell viability. There were no consistent changes in HBV-infected NSC pro- or anti-inflammatory cytokine expression, membrane PDs, proliferative or telomerase activities. CONCLUSIONS: Although the results of this study need to be confirmed, they suggest that HBV infects human NSCs but in the short term, do not alter those NSC features or activities associated with CLD and/or HCC.

Multifocal microcysts and papillary cystadenoma of the lung in von Hippel-Lindau disease.

von Hippel-Lindau disease is an autosomal dominant inherited disorder characterized by a predisposition to multiple neoplasms. Renal cell carcinoma and hemangioblastomas of the retina and cerebellum are the most common of these, but other neoplasms and cysts also occur throughout the body. We report a distinctive, yet never described lung lesion in a 43-year-old woman with von Hippel-Lindau disease. Molecular genetic studies confirmed the presence of a VHL gene mutation in the cells of this lesion. We discuss the salient features of this novel lesion, and hypothesize on its origin and nature.

Impaired Cardiolipin Biosynthesis Prevents Hepatic Steatosis and Diet-Induced Obesity.

Mitochondria are the nexus of energy metabolism, and consequently their dysfunction has been implicated in the development of metabolic complications and progression to insulin resistance and type 2 diabetes. The unique tetra-acyl phospholipid cardiolipin (CL) is located in the inner mitochondrial membrane, where it maintains mitochondrial integrity. Here we show that knockdown of Tafazzin (TAZ kd), a CL transacylase, in mice results in protection against the development of obesity, insulin resistance, and hepatic steatosis. We determined that hypermetabolism protected TAZ kd mice from weight gain. Unexpectedly, the large reduction of CL in the heart and skeletal muscle of TAZ kd mice was not mirrored in the liver. As a result, TAZ kd mice exhibited normal hepatic mitochondrial supercomplex formation and elevated hepatic fatty acid oxidation. Collectively, these studies identify a key role for hepatic CL remodeling in regulating susceptibility to insulin resistance and as a novel therapeutic target for diet-induced obesity.

A whole blood-based perfusate provides superior preservation of myocardial function during ex vivo heart perfusion.

BACKGROUND: Ex vivo heart perfusion (EVHP) provides the opportunity to resuscitate unused donor organs and facilitates assessments of myocardial function that are required to demonstrate organ viability before transplantation. We sought to evaluate the effect of different oxygen carriers on the preservation of myocardial function during EVHP. METHODS: Twenty-seven pig hearts were perfused ex vivo in a normothermic beating state for 6 hours and transitioned into working mode for assessments after 1 (T1), 3 (T3), and 5 (T5) hours. Hearts were allocated to 4 groups according to the perfusate composition. Red blood cell concentrate (RBC, n = 6), whole blood (RBC+Plasma, n = 6), an acellular hemoglobin-based oxygen carrier (HBOC, n = 8), or HBOC plus plasma (HBOC+Plasma, n = 7) were added to STEEN Solution (XVIVO Perfusion, Goteborg, Sweden) to achieve a perfusate hemoglobin concentration of 40 g/liter. RESULTS: The perfusate composition affected the preservation of systolic (T5 dP/dtmax: RBC+Plasma = 903 ± 99, RBC = 771 ± 77, HBOC+Plasma = 691 ± 82, HBOC = 563 ± 52 mm Hg/sec; p = 0.047) and diastolic (T5 dP/dtmin: RBC+Plasma = -574 ± 48, RBC = -492 ± 63, HBOC+Plasma = -326 ± 32, HBOC = -268 ± 22 mm Hg/sec; p < 0.001) function, and the development of myocardial edema (weight gain: RBC+Plasma = 6.6 ± 0.9, RBC = 6.6 ± 1.2, HBOC+Plasma = 9.8 ± 1.7, HBOC = 16.3 ± 1.9 g/hour; p < 0.001) during EVHP. RBC+Plasma hearts exhibited less histologic evidence of myocyte damage (injury score: RBC+Plasma = 0.0 ± 0.0, RBC = 0.8 ± 0.3, HBOC+Plasma = 2.6 ± 0.2, HBOC = 1.75 ± 0.4; p < 0.001) and less troponin-I release (troponin-I fold-change T1-T5: RBC+Plasma = 7.0 ± 1.7, RBC = 13.1 ± 1.6, HBOC+Plasma = 20.5 ± 1.1, HBOC = 16.7 ± 5.8; p < 0.001). Oxidative stress was minimized by the addition of plasma to RBC and HBOC hearts (oxidized phosphatidylcholine compound fold-change T1-T5: RBC+Plasma = 1.83 ± 0.20 vs RBC = 2.31 ± 0.20, p < 0.001; HBOC+Plasma = 1.23 ± 0.17 vs HBOC = 2.80 ± 0.28, p < 0.001). CONCLUSIONS: A whole blood-based perfusate (RBC+Plasma) minimizes injury and provides superior preservation of myocardial function during EVHP. The beneficial effect of plasma on the preservation of myocardial function requires further investigation.

A comparative study of bovine and porcine pericardium to highlight their potential advantages to manufacture percutaneous cardiovascular implants.

RATIONALE: Prosthetic heart valves designed to be implanted percutaneously must be loaded within delivery catheters whose diameter can be as low as 18 F (6 mm). This mandatory crimping of the devices may result in deleterious damages to the tissues used for valve manufacturing. As bovine and porcine pericardial tissue are currently given preference because of their excellent availability and traceability, a preliminary comparative study was undertaken to highlight their potential advantages. MATERIALS AND METHODS: Bovine and pericardium patches were compared morphologically (light microscopy, scanning electron microscopy and transmission electron microscopy). The acute thrombogenicity of both materials was measured in term of platelet uptake and observed by scanning electron microscopy, porcine intact and injured arteries being used as controls. The pericardium specimens were also subjected to uniaxial tensile tests to compare their respective mechanical characteristics. RESULTS: Both pericardiums showed a layered architecture of collagen bundles presenting some interstitial cells. They displayed wavy crimps typical of an unloaded collagenous tissue. The collagen bundles were not bound together and the fibrils were parallel with characteristic periodicity patterns of cross striations. The mesothelial cells found in vivo on the serous surface were no longer present due to tissue processing, but the adjacent structure was far more compacted when compared to the fibrous side. The fibrinocollagenous surfaces were found to be more thrombogenic for both bovine and porcine tissues and the serous side of the porcine pericardium retained more platelets when compared to the bovine samples, making the acute thrombogenicity more important in the porcine pericardium. CONCLUSION: Both bovine and porcine pericardium used in cardiovascular implantology can be selected to manufacture percutaneous heart valves. The selection of one pericardium preferably to the other should deserve additional testing regarding the innocuousness of crimping when loaded in delivery catheters and the long-term durability after percutaneous deployment.

Diffuse intrapulmonary malignant mesothelioma masquerading as interstitial lung disease: a distinctive variant of mesothelioma.

Malignant mesothelioma typically encases lungs as a thick rind, while relatively sparing lung parenchyma. We describe an unusual presentation of mesothelioma characterized by diffuse intrapulmonary growth, with absent or inconspicuous pleural involvement, clinically simulating interstitial lung disease (ILD). We identified 5 patients (median age 56 y, all men) with diffuse intrapulmonary malignant mesothelioma in our pathology consultation practice from 2009 to 2012. Clinical history, imaging, and pathology materials were reviewed. Symptoms included chronic dyspnea (4 cases), cough (3), and acute dyspnea with bilateral pneumothorax (1). Chest imaging showed irregular opacities (5), reticulation (4), pleural effusions (2), and subpleural nodular densities (1), without radiologic evidence of pleural disease or masses. A clinicoradiologic diagnosis of ILD was made in all cases, and wedge biopsies were performed. Histologic evaluation revealed a neoplastic proliferation of bland epithelioid or spindled cells, showing various growth patterns simulating silicotic nodules, desquamative interstitial pneumonia, organizing pneumonia, and Langerhans cell histiocytosis. Some areas mimicked adenocarcinoma, with lepidic, acinar, micropapillary, and solid patterns. Initial diagnoses by referring pathologists included reactive changes (1), hypersensitivity pneumonitis versus drug reaction (1), desquamative interstitial pneumonia versus neoplasm (1), and mesothelioma (2). Microscopic pleural involvement was identified in 4 cases. Immunohistochemistry confirmed the characteristic immunophenotype of mesothelioma in all cases. Median survival of 3 patients treated with chemotherapy was 28 months. Two patients received no therapy and survived 3 and 4 weeks, respectively. "Diffuse intrapulmonary malignant mesothelioma" is a rare variant with a distinctive presentation that clinically mimics ILD. Recognition is essential to avoid misdiagnosis.

A cardioprotective preservation strategy employing ex vivo heart perfusion facilitates successful transplant of donor hearts after cardiocirculatory death.

BACKGROUND: Ex vivo heart perfusion (EVHP) has been proposed as a means to facilitate the resuscitation of donor hearts after cardiocirculatory death (DCD) and increase the donor pool. However, the current approach to clinical EVHP may exacerbate myocardial injury and impair function after transplant. Therefore, we sought to determine if a cardioprotective EVHP strategy that eliminates myocardial exposure to hypothermic hyperkalemia cardioplegia and minimizes cold ischemia could facilitate successful DCD heart transplantation. METHODS: Anesthetized pigs sustained a hypoxic cardiac arrest and a 15-minute warm ischemic standoff period. Strategy 1 hearts (S1, n = 9) underwent initial reperfusion with a cold hyperkalemic cardioplegia, normothermic EVHP, and transplantation after a cold hyperkalemic cardioplegic arrest (current EVHP strategy). Strategy 2 hearts (S2, n = 8) underwent initial reperfusion with a tepid adenosine-lidocaine cardioplegia, normothermic EVHP, and transplantation with continuous myocardial perfusion (cardioprotective EVHP strategy). RESULTS: At completion of EVHP, S2 hearts exhibited less weight gain (9.7 ± 6.7 [S2] vs 21.2 ± 6.7 [S1] g/hour, p = 0.008) and less troponin-I release into the coronary sinus effluent (4.2 ± 1.3 [S2] vs 6.3 ± 1.5 [S1] ng/ml; p = 0.014). Mass spectrometry analysis of oxidized pleural in post-transplant myocardium revealed less oxidative stress in S2 hearts. At 30 minutes after wean from cardiopulmonary bypass, post-transplant systolic (pre-load recruitable stroke work: 33.5 ± 1.3 [S2] vs 19.7 ± 10.9 [S1], p = 0.043) and diastolic (isovolumic relaxation constant: 42.9 ± 6.7 [S2] vs 65.2 ± 21.1 [S1], p = 0.020) function were superior in S2 hearts. CONCLUSION: In this experimental model of DCD, an EVHP strategy using initial reperfusion with a tepid adenosine-lidocaine cardioplegia and continuous myocardial perfusion minimizes myocardial injury and improves short-term post-transplant function compared with the current EVHP strategy using cold hyperkalemic cardioplegia before organ procurement and transplantation.