Effects of prostaglandin E1 on the recovery of ischemia-induced liver mitochondrial dysfunction in rats with cirrhosis

Newly synthesized glycoprotein profiling to identify molecular signatures of warm ischemic injury in donor lungs

Despite recent technological advances such as ex vivo lung perfusion (EVLP), the outcome of lung transplantation remains unsatisfactory with ischemic injury being a common cause for primary graft dysfunction. New therapeutic developments are hampered by limited understanding of pathogenic mediators of ischemic injury to donor lung grafts. Here, to identify novel proteomic effectors underlying the development of lung graft dysfunction, using bioorthogonal protein engineering, we selectively captured and identified newly synthesized glycoproteins (NewS-glycoproteins) produced during EVLP with unprecedented temporal resolution of 4 h. Comparing the NewS-glycoproteomes in lungs with and without warm ischemic injury, we discovered highly specific proteomic signatures with altered synthesis in ischemic lungs, which exhibited close association to hypoxia response pathways. Inspired by the discovered protein signatures, pharmacological modulation of the calcineurin pathway during EVLP of ischemic lungs offered graft protection and improved posttransplantation outcome. In summary, the described EVLP-NewS-glycoproteomics strategy delivers an effective new means to reveal molecular mediators of donor lung pathophysiology and offers the potential to guide future therapeutic development.NEW & NOTEWORTHY This study developed and implemented a bioorthogonal strategy to chemoselectively label, enrich, and characterize newly synthesized (NewS-)glycoproteins during 4-h ex vivo lung perfusion (EVLP). Through this approach, the investigators uncovered specific proteomic signatures associated with warm ischemic injury in donor lung grafts. These signatures exhibit high biological relevance to ischemia-reperfusion injury, validating the robustness of the presented approach.

Fibrotic liver has prompt recovery after ischemia-reperfusion injury

Hepatic ischemia-reperfusion (I/R) is a major complication of liver resection, trauma, and liver transplantation; however, liver repair after I/R in diseased liver has not been studied. The present study sought to determine the manner in which the fibrotic liver repairs itself after I/R. Liver fibrosis was established in mice by CCl4 administration for 6 wk, and then liver I/R was performed to investigate liver injury and subsequent liver repair in fibrotic and control livers. After I/R, fibrotic liver had more injury compared with nonfibrotic, control liver; however, fibrotic liver showed rapid resolution of liver necrosis and reconstruction of liver parenchyma. Marked accumulation of hepatic stellate cells and macrophages were observed specifically in the fibrotic septa in early reparative phase. Fibrotic liver had higher numbers of hepatic stellate cells, macrophages, and hepatic progenitor cells during liver recovery after I/R than did control liver, but hepatocyte proliferation was unchanged. Fibrotic liver also had significantly greater number of phagocytic macrophages than control liver. Clodronate liposome injection into fibrotic mice after I/R caused decreased macrophage accumulation and delay of liver recovery. Conversely, CSF1-Fc injection into normal mice after I/R resulted in increased macrophage accumulation and concomitant decrease in necrotic tissue during liver recovery. In conclusion, fibrotic liver clears necrotic areas and restores normal parenchyma faster than normal liver after I/R. This beneficial response appears to be directly related to the increased numbers of nonparenchymal cells, particularly phagocytic macrophages, in the fibrotic liver.NEW & NOTEWORTHY This study is the first to reveal how diseased liver recovers after ischemia-reperfusion (I/R) injury. Although it was not completely unexpected that fibrotic liver had increased hepatic injury after I/R, a novel finding was that fibrotic liver had accelerated recovery and repair compared with normal liver. Enhanced repair after I/R in fibrotic liver was associated with increased expansion of phagocytic macrophages, hepatic stellate cells, and progenitor cells.

Perioperative prostaglandin e1 infusion in living donor liver transplantation: A double-blind, placebo-controlled randomized trial

The role of prostaglandin E1 (PGE1) infusion in improving early graft function has not been well defined, especially in the scenario of living donor liver transplantation (LDLT). We designed a randomized, double-blind, placebo-controlled trial to evaluate the role of perioperative PGE1 infusion in LDLT. Patients in the study arm received PGE1 (alprostadil) at the rate of 0.25 μg/kg/hour, starting at 1 hour after portal venous reperfusion, and continued for 96 hours. The primary endpoint was early allograft dysfunction (EAD). We analyzed multiple secondary endpoints including postoperative liver function and renal function parameters, acute kidney injury (AKI), hepatic artery thrombosis (HAT), postoperative bleeding, overall mortality, and posttransplant hospital stay. The incidence of EAD was lower in the PGE1 arm, although the difference did not reach statistical significance (22.4% versus 36%; P = 0.21). Among the secondary endpoints, the incidence of AKI was significantly lower in the PGE1 arm (8.2% versus 28%; P = 0.02), as were the peak and mean postoperative creatinine levels. The need for renal replacement therapy was similar between the 2 groups. Among the postoperative graft function parameters, postoperative alanine aminotransferase level was significantly lower in the PGE1 arm (P = 0.04), whereas the remaining parameters including serum bilirubin, aspartate aminotransferase, and international normalized ratio were similar between the 2 arms. There was no difference in the incidence of HAT and postoperative bleeding, in-hospital mortality, and posttransplant hospital stay between the 2 arms. Perioperative PGE1 infusion reduces the incidence of posttransplant renal dysfunction in patients undergoing LDLT. Liver Transplantation 22 1067-1074 2016 AASLD.

The PRAISE study: a prospective, multi-center, randomized, double blinded, placebo-controlled study for the evaluation of iloprost in the early postoperative period after liver transplantation (ISRCTN12622749)

Background

Liver graft dysfunction can deteriorate to complete organ failure and increases perioperative morbidity and mortality after liver transplantation. Therapeutic strategies reducing the rate of graft dysfunction are of current clinical relevance. One approach is the systemic application of prostaglandins, which were demonstrated to be beneficial in reducing ischemia-reperfusion injury. Preliminary data indicate a positive effect of prostacyclin analogue iloprost on allograft viability after liver transplantation. The objective of the study is to evaluate the impact of iloprost in a multi-center trial.

Methods/Design

A prospective, double-blinded, randomized, placebo-controlled multicenter study in a total of 365 liver transplant recipients was designed to assess the effect of intravenous iloprost after liver transplantation. Primary endpoint will be the primary graft dysfunction characterized as presentation of one or more of the following criteria: ALAT or ASAT level > 2000 IU/ml within the first 7 postoperative days, bilirubine ≥ 10 mg/dl on postoperative day 7; INR ≥ 1.6 on postoperative day 7 or initial non-function. Secondary endpoints are parameters of post-transplant morbidity, like rates of infections, biliary complications, need of clotting factors or renal replacement therapy and the graft and patient survival.

Discussion

A well-established treatment concept to avoid graft dysfunction after liver transplantation does not exist at the moment. If the data of this research project confirm prior findings, iloprost would improve the general outcome after liver transplantation.

Trial Registration

German Clinical Trials Register: DRKS00003514. Current Controlled Trials Register: ISRCTN12622749.

Impact of stable PGI₂ analog iloprost on early graft viability after liver transplantation: a pilot study

BACKGROUND

Ischemia/reperfusion injury after liver transplantation (LT) may be associated with primary graft dysfunction (PDF) or non-function. Prostaglandins were demonstrated to be beneficial in reducing ischemic injury by improving microcirculation and protecting endothelial cells. The aim of this study was to analyze the effect of the continuously administered prostaglandin I(2) analog iloprost on allograft function after LT.

METHODS

Eighty patients were prospectively randomized and assigned to two groups. Patients in the treatment group received iloprost for seven d after transplantation, and those in the control group did not. The primary end point was graft dysfunction.

RESULTS

The incidence of PDF was 20% (n = 8) in the control group and 5% (n = 2) in the treatment group, respectively (p = 0.087). Four patients in the control group underwent re-transplantation for initial non-function (INF). There was no evidence for INF in the treatment group. Iloprost was associated with improved allograft function. Clinical course and outcome were comparable.

CONCLUSIONS

We suggest iloprost to be beneficial for early post-transplant liver function. If the rate of PDF can be significantly reduced with this treatment concept, it should be analyzed in a larger number of patients (ISRCTN95672167).

Study of rat hepatocytes in primary culture submitted to hypoxia and reoxygenation: action of the cytoprotectors prostaglandin E1, superoxide dismutase, allopurinol and verapamil

CONTEXT: Exposure of hepatocytes to pathological conditions in a microenvironment of hypoxia and reoxygenation is very frequent in hepatic diseases. Several substances present perspectives for cytoprotective action on hepatocyte submitted to reoxygenation after hypoxia and simple hypoxia. OBJECTIVE: We research therapeutic options for hepatocytes submitted to hypoxia and hypoxia + reoxygenation injury. METHODS: Primary culture of rat hepatocytes was submitted to hypoxia (2 hours) plus reoxygenation (2 hours) and simple hypoxia (4 hours) in the presence or the absence of cytoprotectors. The hepatocyte lesion was evaluated by functional criteria through percentage of lactate dehydrogenase released and cell viability. The effects of the cytoprotectors prostaglandin E1 3 ηg/mL, superoxide dismutase 80 μg/mL, allopurinol 20 μM and verapamil 10-4 M were studied in this model of injury. RESULTS: Reoxygenation after hypoxia induced more significant lesion in cultured hepatocytes compared to simple hypoxia, detected by analysis of functional criteria. There was a significant reduction of percentage of lactate dehydrogenase released and a significant increase of percentage of cell viability in the hypoxia + reoxygenation + cytoprotectors groups compared to hypoxia + reoxygenation groups. Prostaglandin E1, superoxide dismutase and verapamil also protected the group submitted to simple hypoxia, when evaluated by functional criteria. CONCLUSIONS: We conclude that reoxygenation after hypoxia significantly increased the lesion of cultured rat hepatocytes when compared to simple hypoxia. Prostaglandin E1, superoxide dismutase, allopurinol and verapamil acted as cytoprotectors to the rat cultured hepatocytes submitted to hypoxia + reoxygenation in vitro. The substances prostaglandin E1, superoxide dismutase and verapamil protected hepatocytes submitted to simple hypoxia on the basis of all the criteria studied in this experimental model.

A atividade respiratória mitocondrial é um bom parâmetro para a lesão por isquemia e reperfusão hepática?

RACIONAL: A atividade respiratória das mitocôndrias está associada à lesão por isquemia e reperfusão do fígado. OBJETIVO: Investigar in vitro se há obrigatoriedade de impedimento da respiração mitocondrial para que a lesão por isquemia e reperfusão do fígado possa ser detectada. MATERIAIS E MÉTODOS: Vinte e quatro cães de ambos os gêneros foram divididos nos seguintes grupos: controle, cães operados sem sofrer isquemia ou reperfusão hepática; I60, cães submetidos a 60 minutos de isquemia do fígado; I30/R60, cães submetidos a 30 minutos de isquemia e 60 minutos de reperfusão do fígado e I45/R120, cães submetidos a 45 minutos de isquemia e 120 de reperfusão do fígado. Amostras de fígado foram obtidas para dosagem de malondialdeído, para estudo da respiração mitocondrial por meio de traços polarográficos e para avaliação do potencial de membrana mitocondrial. Sangue foi obtido para dosagem de transaminases e desidrogenase lática. RESULTADOS: O grupo I45/R120 apresentou evidente aumento dos valores de transaminases, desidrogenase lática, aumento dos valores de malondialdeído e tendência à diminuição da respiração mitocondrial estimulada por adenosina difosfato, sem haver prejuízo irreversível para a fosforilação oxidativa ou para o potencial de membrana mitocondrial. CONCLUSÃO: A lesão por isquemia e reperfusão do fígado do cão pode ser documentada sem que haja prejuízo demonstrável para a função mitocondrial. Dados referentes à respiração mitocondrial podem não mostrar diferenças significativas em relação aos controles, mesmo em situações de evidente lesão tecidual por isquemia e reperfusão do fígado.

Effect of short-term administration of prostaglandin E1 on viability after ischemia/reperfusion injury with extended hepatectomy in cirrhotic rat liver

The cytoprotective effect of prostaglandin E(1) (PGE(1)) has been demonstrated experimentally and clinically against hepatic ischemia and reperfusion injury and against the effects of partial hepatectomy in both individual and combined models of noncirrhotic livers. Cirrhotic livers are more vulnerable to ischemia/reperfusion injury during hepatectomy than are noncirrhotic livers, and postoperative malfunctioning complicates life with multiple organ failure. Cirrhotic livers with tumors have mostly been treated conservatively because extended hepatectomy with induced ischemia during surgery is impossible. The purpose of our study was to document postoperative surgical adaptation in inoperable cases with improved survival after extended hepatectomy in a rat model of cirrhosis treated by PGE(1). Cirrhosis was induced by intraperitoneal injections of 1% dimethylnitrosamine. The liver was subjected to 15 minutes of total ischemia by occluding the hepatoduodenal ligament. Hepatectomy was performed during ischemia. Pretreatment with PGE(1) (0.4 microg/kg/min) (or without it in the controls) was given for 15 minutes by intravenous infusion prior to inducing ischemia and during reperfusion. Portal venous flow (PVF) and liver tissue blood flow (LTBF) were measured during reperfusion. At the end of 60 minutes of reperfusion, venous blood was collected for liver function tests. The animals were followed up regarding survival for 48 hours. The PVF and LTBF were significantly improved in the PGE(1) group. The blood chemical analysis indicated that PGE(1) significantly suppressed posthepatectomy liver dysfunction. Most importantly, PGE(1) treatment markedly improved the survival rate, from 42% in the controls to 75% in the test animals at 24 hours after hepatectomy and from 17% in the controls to 58% in the test animals at 48 hours. We concluded that short-term administration of PGE(1) makes extensive hepatectomy possible under ischemic conditions in cirrhotic livers.

Differentiated therapy with prostaglandin E1 (alprostadil) after orthotopic liver transplantation: the usefulness of procalcitonin (PCT) and hepatic artery resistive index (RI) for the evaluation of early graft function and clinical course

Increasing demand for donor organs has led to new pharmacological concepts for reducing ischemia-reperfusion injury (I/R) of the graft after liver transplantation to prevent primary non-functioning of the organ. Prostaglandins have proved to be cytoprotective in several experimental models of ischemia and transplantation. The prophylactic administration after orthotopic liver transplantation is still a subject of controversial discussion. The aim of our study was the evaluation of the post-transplant hepatic artery resistive index (RI) measured by color Doppler imaging, in combination with postoperative elevation of transaminases, as parameters indicating the need for a differentiated systemic therapy with prostaglandin E1 (PGE1) (alprostadil). In addition, the value of serum procalcitonin (PCT) as a postoperative parameter for the extent of I/R is investigated. In the case of post-transplant elevated hepatic artery RI (RI > 0.75), the administration of PGE1 led to a significant reduction of transaminases (p < 0.05) and a decline of the RI. In addition, postoperative PCT levels could be reduced significantly by PGE1 application. These results suggest that determination of RI is feasible for indicating a need for therapy with PGE1. Its targeted application reduces hepatocellular damage due to I/R after liver transplantation.

Effects of cold and warm ischemia on the mitochondrial oxidative phosphorylation of swine lung

BACKGROUND

The aim of the study was to investigate the consequence of warm and cold ischemia on lung mitochondria in order to define bioenergetic limits within lung could be suitable for pulmonary transplantation.

METHODS

Twenty-two pigs underwent lung harvesting after lung flush with Euro-Collins solution. Mitochondria were isolated from fresh lungs, from lungs submitted to 24 or 48 hr of cold ischemia, to 30 or 45 min of warm ischemia, and to 30 min of warm ischemia followed by 24 or 48 hr of cold ischemia. Mitochondrial oxidative phosphorylation parameters were determined in isolated mitochondria by in vitro measurement of oxygen consumption.

RESULTS

Relative to controls, mitochondria submitted to cold ischemia showed an alteration in the oxidoreductase activities of the respiratory chain but no membrane permeability alteration. After 48 hr of cold ischemia, there was a decrease in the yield of the oxidative phosphorylation. Thirty minutes of warm ischemia did not alter the mitochondrial respiratory parameters. However, lung submitted to 45 min of warm ischemia showed mitochondrial damage as a decrease in the oxidative phosphorylation efficiency and ADP availability but no change in the oxidoreductase activities. Relative to cold ischemia alone, 30 min of warm ischemia preceding cold ischemia promoted no significant change in the respiratory parameters.

CONCLUSIONS

On bioenergetic basis, lung submitted to warm ischemia could be suitable for transplantation if the warm ischemia duration does not exceed 30 min. This could be a major concern in lung procurement from non-heart beating donors.

Mechanism and prevention of ischemia-reperfusion injury of the liver

Interruption of liver blood flow is often necessary as an operative technique in liver surgery. However, this procedure causes liver damage and can be a factor in postoperative liver failure. Interruption of oxygen and substrate supply and accumulation of metabolites contribute to a great variety of cellular and subcellular dysfunctions. Impairment of liver microcirculation occurs after reperfusion. It has been presumed that there is an imbalance between the activities of vasoconstrictors and vasodilators which would determine the vascular condition during ischemia and reperfusion phases. Some mediators are known to act as cytotoxic factors, especially after reperfusion following ischemia. The phenomenon in which organ damage becomes worse, even after reperfusion, is called reperfusion injury. Mediators released from accumulated polymorphonuclear neutrophils and activated Kupffer cells such as oxygen radicals and inflammatory cytokines are associated with ischemia-reperfusion injury of the liver. Regulation of these mediators will be a therapeutic necessity for this kind of liver injury in the future.

Effect of prostaglandin E1 on hepatic function after hepatectomy in patients with chronic liver disease

We designed a clinical study to determine the effect of prostaglandin E1 (PGE1) on functional recovery of the liver after hepatectomy. Thirty-five patients with primary hepatic neoplasms accompanied by chronic liver disease were randomly divided into two groups: 13 patients received intravenous PGE1 at 0.06 micro g/kg per minute for 3 postoperative days (PGE1[+] group) and 22 patients did not (PGE1[-] group). All postoperative values of hepatic function tests were calculated as a ratio to each preoperative value. Significantly higher cholinesterase ratios were observed in the PGE1[+] group than in the PGE1[-] group 2 weeks postsurgery (P < 0.05). The alanine aminotransferase (ALT) ratios at 1 and 2 weeks postsurgery were 118% and 123% in the PGE1[+] group and 207% and 175% in the PGE1[-] group, respectively. The ratio of the maximum postoperative ALT level was 503% in the PGE1[+] group and 792% in the PGE1[-] group (P < 0.05). We concluded that PGE1 would have the effect of conditioning the postoperative ALT elevation and cholinesterase deterioration and that the patient's postoperative course might be more favorable with the use of PGE1.

Nicotinamide methylation and hepatic energy reserve: a study by liver perfusion in vitro

BACKGROUND/AIMS

The synthesis of pyridine nucleotides from nicotinamide requires adenosine triphosphate. In man when exogenous nicotinamide is poorly utilized in this synthesis, the excess follows a dissipative metabolic pathway and is excreted in urine as N-methylnicotinamide. In human cirrhosis N-methylnicotinamide serum levels are higher than normal, in basal condition and after nicotinamide oral load. The aim of this study was to verify N-methylnicotinamide production in relation to hepatic content of adenosine triphosphate during in vitro perfusion of rat liver, in normal conditions and after adenosine triphosphate depletion by metabolic stress.

METHODS

"Stress" was obtained by pre-washing with saline for 15 min before the perfusion with nutritive medium.

RESULTS

The adenosine triphosphate decrease in the stressed liver was 38% after pre-washing with saline and 80% at the end of nutritive perfusion. In control liver the corresponding decreases were 1% after pre-washing with nutritive medium and 65% at the end of perfusion with the same medium. The total nicotinamide adenine dinucleotide decreases were 44% and 56% in the stressed liver, and 19% and 52% in the control liver. The output levels of N-methylnicotinamide at 90 min of rat liver nutritive perfusion were 31.50 +/- 4.72 nmol/g for normal liver and 66.40 +/- 13.17 for stressed liver (p<0.001). Liver adenosine triphosphate was inversely related to N-methylnicotinamide production (r=0.93; p<0.001).

CONCLUSIONS

These data suggest that nicotinamide methylation may be enhanced when there is hepatic adenosine triphosphate decrease and energy failure induced by hypoxia or metabolic stress, similar to that obtained in vitro by saline washing before perfusion with nutritive medium. This study shows that the evaluation of N-methylnicotinamide production in man (before and after nicotinamide load) might be useful to explore the energy state of diseased liver.

Prostaglandin E1 abrogates early reductive stress and zone-specific paradoxical oxidative injury in hypoperfused rat liver

This study was designed to investigate the effects of prostaglandin E1 on reductive stress and the subsequent oxidative cell injury in hypoperfused rat liver. The intralobular heterogeneity of hepatocellular redox state, mitochondrial dysfunction, and intracellular hydroperoxide formation were visually monitored by digital microfluorography of pyridine nucleotide autofluorescence, rhodamine 123, and dichlorofluorescein fluorescence, respectively. Under the 25% low flow perfusion, pyridine nucleotide autofluorescence increased time-dependently and reached a steady state at 10 min among the entire lobules. The decrease in mitochondrial membrane potential was > 20 mV in all portions of the lobules at 60 min. The onset of hydroperoxide formation was observed at 40 min in the marginally oxygenated proximal portion of anoxic pericentral regions and the oxidative impact reached a maximum level at 60 min. Sodium (-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazo [1,5-a]-1,3,5-triazine-4-olate monohydrate (BOF 4272), a novel xanthine oxidase inhibitor, suppressed the zone-specific oxidative changes without attenuating the increase in pyridine nucleotide autofluorescence and mitochondrial dysfunction. Pretreatment with prostaglandin E1 not only abrogated an early increase in pyridine nucleotide fluorescence and mitochondrial dysfunction induced by hypoperfusion but also diminished the subsequent midzonal oxidative injury. Since prostaglandin E1 has no oxyradical-scavenging action, the preventive effect of this reagent on the hypoxia-induced oxidative cell injury is attributable to the attenuation of mitochondrial dysfunction. These results suggest that, in low flow hypoxia, early reductive stress plays a key role in the initiation of xanthine oxidase-mediated midzonal oxidative changes, which may lead to subsequent centrilobular necrosis.

Hepatic and gastric cytoprotective effects of long-term prostaglandin E1 administration in cirrhotic rats

BACKGROUND

Acute administration of prostaglandin E (PGE) may be cytoprotective for hepatocytes in acute hepatitis and for gastric mucosa in cirrhotic rats. We examined the effects of long-term PGE treatment on liver and stomach in cirrhotic rats.

METHODS

Cirrhosis was induced by bile duct ligation. Controls had a sham operation. Half the rats received a PGE1 analogue, misoprostol (PGE1) (10 micrograms orally, daily) on days 1-29 postsurgery, and the others received vehicle only. On day 31, all rats underwent ex vivo gastric chamber procedures. Liver chemistry, portal pressures, and hepatic and gastric tissue levels of prostaglandin E2, leukotriene B4, myeloperoxidase, and collagen were determined.

RESULTS

PGE1-treated cirrhotic rats had less hepatosplenomegaly, lower serum alanine aminotransferase levels, and portal pressures and higher arterial pressure than vehicle-treated cirrhotic rats. Hepatic and gastric leukotriene B4, myeloperoxidase and collagen levels were significantly lower in the PGE1-treated compared with vehicle-treated cirrhotic rats. Vehicle-treated cirrhotic rats had greater spontaneous and ethanol-induced gastric damage and failed to show a gastric hyperemic response to ethanol, whereas PGE1-pretreated rats did. PGE1 did not significantly affect sham-operated rats.

CONCLUSIONS

Long-term PGE1 administration was cytoprotective for both the liver and gastric mucosa in cirrhotic rats. Clinical trials of PGE in human cirrhosis or portal hypertensive gastropathy may be warranted.

Transcatheter hepatic arterial drug infusion therapy for hepatocellular carcinoma. Effect on the arterial ketone body ratio

The arterial ketone body ratio (acetoacetate to beta-hydroxybutyrate) was measured in 15 patients with chronic liver disease before and after the infusion of anticancer drugs or embolic agents (gelatin sponge or iodized oil) into the hepatic artery. The arterial ketone body ratio decreased after hepatic angiography and decreased further at 15 min after infusion therapy. When the arterial ketone body ratio decreased to 1.0 or less on at least one occasion after infusion therapy, the ratio after hepatic angiography was always 1.35 or less. Such patients developed marked systemic symptoms like fever and severe liver dysfunction. Ascites also developed in three patients in whom the arterial ketone body ratio was reduced to 0.7 or less at 24 h after infusion therapy. The arterial ketone body ratios improved at 3-7 days after infusion therapy. In the seven patients treated with gelatin sponge embolization, the ratio at 3-7 days after therapy was actually higher than that before angiography.