Surgical stress response in robot-assisted versus laparoscopic surgery for colon cancer (SIRIRALS): randomized clinical trial

BACKGROUND

Evidence for the routine use of robotic technology and its impact on short-term outcomes in colon cancer surgery is lacking. The aim of this study was to compare the surgically induced systemic stress response and clinical and patient-reported outcomes for patients undergoing robot-assisted or laparoscopic colon cancer surgery.

METHODS

In this double-blinded superiority RCT completed between August 2021 and March 2023, patients with stage 1-3 colon cancer were randomized in a 1 : 1 ratio to undergo either robot-assisted or laparoscopic colon cancer surgery. The primary outcome was changes in the systemic stress response, characterized by C-reactive protein expression in the first three postoperative days. Secondary outcomes were intraoperative and postoperative complications and patient-reported outcomes. The latter included quality of recovery-15 and pain intensity using a visual analogue scale.

RESULTS

In total, 128 patients were screened for potential inclusion in this study; 50 patients (25 in the robot-assisted group and 25 in the laparoscopic group) were included in the final follow-up and analysis. The postoperative C-reactive protein response was higher on the first postoperative day in the laparoscopic group (mean difference = 19.88 mg/l, 95% c.i. 3.89-35.86; P = 0.045). No statistically significant differences were noted for C-reactive protein expression on the second and third postoperative days.

CONCLUSION

Adopting robot-assisted surgery for stage 1-3 colon cancer is associated with a reduction in the surgical stress response.

REGISTRATION NUMBER

NCT04687384 (http://www.clinicaltrials.gov).

Robot-assisted versus laparoscopic short- and long-term outcomes in complete mesocolic excision for right-sided colonic cancer: a systematic review and meta-analysis

BACKGROUND

Complete mesocolic excision (CME) surgery is increasingly implemented for the resection of right-sided colonic cancer, possibly resulting in improved 5-year overall and disease-free survival compared to non-CME surgery. However, it is not clear what surgical platform should be used. The aim of this study was to compare the following outcomes between robot-assisted and laparoscopic CME-surgery for right-sided colonic cancer: (i) short-term clinical outcomes, (ii) pathological specimen quality, and (iii) long-term oncological outcomes.

METHODS

Medline, Embase, and Cochrane Database of Systematic Reviews were searched from inception until August 2021. Pooled proportions were calculated by applying the inverse variance method. Heterogeneity was explored by I-square and supplemented by sensitivity- and meta-regression analyses. The risk of bias was evaluated by either MINORS or Cochrane's risk-of-bias tool (RoB 2).

RESULTS

Fifty-five studies with 5.357 patients (740 robot-assisted and 4617 laparoscopic) were included in the meta-analysis. Overall postoperative morbidity was 17% [95% CI (14-20%)] in the robot-assisted group and 13% [95%CI (12-13%)] in the laparoscopic group. Robot-assisted CME was associated with a shorter hospital stay, lower intraoperative blood loss, a higher amount of harvested lymph nodes, and better 3-year oerall and disease-free survival. MINORS and RoB2 indicated a serious risk of bias across studies included.

CONCLUSIONS

This review which includes predominantly non-randomized studies suggests a possible advantage of the robot-assisted CME compared with a laparoscopic technique for several short-term outcomes.

P-014 RISK FACTORS FOR SHORT- AND LONG-TERM COMPLICATIONS FOLLOWING VENTRAL HERNIA REPAIR WITH THE PERITONEAL FLAP TECHNIQUE

Aim

The peritoneal flap technique has been introduced for the repair of complex abdominal wall defects. The present study was conducted to determine the association between preoperative risk factors and the incidence of short and long-term complications.

Material & Methods

Patients undergoing abdominal wall repair between January 2010 and September 2020 were included in the study. Patient files were retrospectively reviewed and the presence of risk-factors and the incidence of postoperative short and long-term complications were recorded. A multivariable logistic regression analysis was used to estimate odds ratio (OR) for postoperative complications.

Results

327 patients were included. 48.0% were male. Median body mass index(BMI) was 30.9, 13.8% had diabetes and 23.2% were active smokers. Median defect size was 8 cm2 and median mesh size was 667.5 cm2. Median length of hospital stay was 5 days. 13.1% of patients developed a superficial wound infection, 10.4% seroma and 1.2% skin necrosis. Chronic pain was observed in 4.6% and recurrence in 2.4%. The regression analysis demonstrated a stepwise increase in OR for short and long-term complications. This risk was increased by 10% per unit BMI (P<0.01). Smoking and hernial defect size contributed only to a minor extent to the risk of postoperative complications.

Conclusion

The peritoneal flap method is a safe procedure associated with a low risk of recurrence. The risk of complications is associated with BMI whereas smoking and hernial defect size only contributes to a minor extent.

P-009 OPEN VS LAPAROSCOPIC VS ROBOT-ASSISTED INGUINAL HERNIA REPAIR: A CASE SERIES

Aim

Minimally invasive inguinal hernia repair is thought to be associated with fewer complications. To address this hypothesis, we compared short- and long-term complications in patients undergoing elective open (Lichtenstein), laparoscopic (TAPP) and robot-assisted inguinal hernia repair (rTAPP).

Material & Methods

Patients undergoing either, Lichtenstein, TAPP or rTAPP at our institution between January 1st 2017 and December 30th 2019 were retrospectively identified. Short (haematoma, seroma, surgical-site infections) and long-term complications (chronic pain, recurrence) were recorded and compared between groups.

Results

636 patients were included in the study. 370 were treated with Lichtenstein, 125 TAPP and 141 with rTAPP. There was a significant overweight of men in all groups (p < 0,001). Among the rTAPP group, the overall rate of complications was reduced (open: 10.0%; laparoscopic: 8.8%; robot-assisted 5.7%) while the presence of chronic pain was slightly more prevalent (Lichtenstein: 1.6%; TAPP: 1.6%; rTAPP: 2.1%). The rate of recurrence was lower following rTAPP (Lichtenstein: 3.8%; TAPP: 2.4%; rTAPP: 1.4%). Same day discharged was more likely following the open technique (open: 88.9%; laparoscopic: 78.4%; robot-assisted 78.7%). Nevertheless, these results were not statistically significant (p>0.05).

Conclusions

The present case series demonstrates a comparable rate of short and long-term complications following open and minimally invasive inguinal hernia repair. The trend towards a lower overall complications rate and recurrence rate, though not statistically significant, implies that minimally invasive surgery might be associated with a lower complication and recurrence rate. However, a larger prospective study design with a longer follow-up is needed to test this hypothesis.

P096 QUALITY OF LIFE FOLLOWING ROBOTIC-ASSISTED RETROMUSCULAR VENTRAL HERNIA REPAIR

Aim

Robotic-assisted ventral hernia repair (rVHR) has emerged as an alternative to current open and laparoscopic procedures. The present study aims to determine the effect of rVHR on postoperative quality of life.

Material and Methods

Patients undergoing elective rVHR from 01/01 2017 until 12/6 2020 were identified from the hospitaĺs electronic medical record system. Patient demographic, clinical presentation, location of the hernial defect and postoperative complications were obtained from the case notes. A phone interview was also conducted to assess postoperative life quality using the EuraHS-QoL questionnaire. The pre and postoperative life quality assessment was performed to determine the effect of robotic-assisted ventral hernia repair on 1. Pain at the site of the hernia, 2. Restrictions of activities due to pain or discomfort at the site of the hernia and 3. Esthetical discomfort. Moreover, patients were asked whether they felt their overall quality of life had improved, deteriorated or was unaltered after the procedure. A Wilcoxon signed rank test was conducted to determine the effect of the repair on postoperative life quality.

Results

85 out of 99 patients completed the interview and were included in this case series. The survey revealed a highly significant improvement of life quality in all categories (P < 0. 01). 86% of the participants reported that their overall quality of life had improved, 13% reported no change and 1% felt that it had deteriorated.

Conclusions

Robotic-assisted retromuscular ventral hernia repair is a safe procedure that is associated with a significant improvement of patient quality of life.

P097 SHORT AND LONG-TERM COMPLICATIONS FOLLOWING ROBOTIC-ASSISTED RETROMUSCULAR VENTRAL HERNIA REPAIR

Aim

Robotic-assisted ventral hernia repair (rVHR) has become an attractive alternative to current laparoscopic and open procedures. The present study aims to determine short-and long-term complications following rVHR

Material and Methods

Patients undergoing rVHR from 01/01 2017 until 21/06 2020 were identified from the electronic medical record system. The medical case notes were reviewed and a telephone interview conducted to determine short and long-term complications. Patients with symptoms related to the repair were examined by a specialist in hernia surgery. US or CT scan was performed to determine the presence of absence of complications

Results

85 patients were included. Mean age was 57.8 years, 54 were males (63.5%). Mean ASA-score was 2.12 and BMI was 30.2 kg/m2. 11 patients (13%) had diabetes, 22 (26%) were active smokers, 37 (44%) had hypertension and 7 (8%) were taking anti-coagulants. The mean hernial defect was 16.1 cm2 and the mesh size was 205.4 cm2. Mean length of stay was 0.5 days and the follow-up time was 94 weeks. Hematoma was encountered in 10 (11.8%) patients. 8 (9.4%) reported of seroma and 1 (1.2%) of a superficial wound infection complicated by skin necrosis. 5 patients (5.9%) reported of chronic pain. 2 patients (2.3%) developed recurrence.

Conclusions

The study demonstrates that rVHR is feasible and associated with few complications and a very low recurrence rate. Patients who had pain before surgery were likely to have less pain following the procedure. Due to the short hospital stay the procedure is suitable as an outpatient procedure.

Systemic inflammatory response in robot-assisted and laparoscopic surgery for colon cancer (SIRIRALS): study protocol of a randomized controlled trial

Background

Robot-assisted surgery is being increasingly adopted in treating colorectal cancer, and the transition from laparoscopic surgery to robot-assisted surgery is a trend. The evidence of the benefits of robot-assisted surgery is sparse. However, findings are associated with improved patient-related outcomes and overall morbidity rates compared to laparoscopic surgery. This induction is unclear, considering both surgical modalities are characterized as minimally invasive. This study aims to evaluate the systemic and peritoneal inflammatory stress response induced by robot-assisted surgery compared with laparoscopic surgery for elective colon cancer resections in a prospective, randomized controlled clinical trial.

Methods

This study is a single-centre randomized controlled superiority trial with 50 colon cancer participants. The primary endpoint is the level of systemic inflammatory response expressed as serum C-reactive protein (CRP) and interleukin 6 (IL-6) levels between postoperative days one and three. Secondary endpoints include (i) levels of systemic inflammation in serum expressed by a panel of inflammatory and pro-inflammatory cytokines measured during the first three postoperative days, (ii) postoperative surgical and medical complications (30 days) according to Clavien-Dindo classification and Comprehensive Complication Index, (iii) intraoperative blood loss, (iv) conversion rate to open surgery, (v) length of surgery, (vi) operative time, (vii) the number of harvested lymph nodes, and (viii) length of hospital stay. The exploratory endpoints are (i) levels of peritoneal inflammatory response in peritoneal fluid expressed by inflammatory and pro-inflammatory cytokines between postoperative day one and three, (ii) patient-reported health-related quality of recovery-15 (QoR-15), (iii) 30 days mortality rate, (iv) heart rate variability and (v) gene transcript (mRNA) analysis.

Discussion

To our knowledge, this is the first clinical randomized controlled trial to clarify the inflammatory stress response induced by robot-assisted or laparoscopic surgery for colon cancer resections.

Trial registration This trial is registered at Clinicaltrials.gov (Identifier: NCT04687384) on December, 29, 2020, Regional committee on health research ethics, Region of Southern Denmark (N75709) and Data Protection Agency, Hospital Sønderjylland, University Hospital of Southern Denmark (N20/46179).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01355-4.

Improved perioperative outcomes and reduced inflammatory stress response in malignant robot-assisted colorectal resections: a retrospective cohort study of 298 patients

Background

Robot-assisted surgery is increasingly implemented for the resection of colorectal cancer, although the scientific evidence for adopting this technique is still limited. This study’s main objective was to compare short-term complication rates, oncological outcomes, and the inflammatory stress response after colorectal resection for cancer performed laparoscopic or robot-assisted.

Methods

We conducted a retrospective cohort study comparing the robot-assisted approach to laparoscopic surgery for elective malignant colorectal neoplasm. Certified colorectal and da Vinci ® robotic surgeons performed resections at a Danish tertiary colorectal high volume center from May 2017 to March 2019. We analyzed the two surgical groups using uni- and multivariate regression analyses to detect differences in intra- and postoperative clinical outcomes and the inflammatory stress response.

Results

Two hundred and ninety-eight patients were enrolled in the study. Significant differences favoring robot-assisted surgery was demonstrated for; length of hospital stay (4 days, interquartile range (4, 5) versus 5 days, interquartile range (4–7), p < 0.001), and intraoperative blood loss (50 mL, interquartile range (20–100) versus 100 mL, interquartile range (50–150), p < 0.001) compared to laparoscopic surgery. The inflammatory stress response was significantly higher after laparoscopic compared to robot-assisted surgery reflected by an increase in C-reactive protein concentration (exponentiated coefficient = 1.23, 95% confidence interval (1.06–1.46), p = 0.008). No differences between the two groups were found concerning mortality, microradical resection rate, conversion to open surgery, and surgical or medical short-term complication rates.

Conclusion

Robot-assisted surgery is feasible and can be safely implemented for colorectal resections. The robot-assisted approach, when compared to laparoscopic surgery, was associated with improved intra- and postoperative outcomes. Extensive prospective studies are needed to determine the short- and long-term outcomes of robotic surgery for colorectal cancer.

Improved recovery after cold crystalloid cardioplegia using low-dose glutamate enrichment during reperfusion after aortic unclamping: a study in isolated blood-perfused pig hearts

Increased glutamate utilization is a part of the metabolic adaptation to oxygen deprivation by the heart. The effect of low-dose L-glutamate (2 mmol/L) during continuous reperfusion after aortic unclamping on postcardioplegic recovery was studied in pig hearts similar in size, anatomy, and function to the human adult heart. After cold crystalloid cardioplegic arrest (CCC) with Bretschneider solution no 3, hearts were excised from pigs weighing 70-80 kgs (heart weight, average +/- SEM: 308 +/- 4 grams), and reperfused in an isolated blood-perfused heart model for 120 minutes. Three groups of hearts were compared. One group of hearts was subjected to 30 minutes of CCC only (30 min group; n = 9), another group of hearts to 90 minutes of CCC and storage (Control group: n = 16), and a third group to 90 minutes of CCC and storage, but with L-glutamate added to the blood reperfusate (2 mmol/L) (Glutamate group: n = 18). In the Control group 14 of 16 hearts (88%) needed electrical defibrillation after start of reperfusion, significantly more (p < 0.05) than the 8 of 18 (44%) in the Glutamate group; the difference between the 30-min (2 of 9 [22%]) and the Glutamate group was not significant (p = 0.48). Developed left-ventricular pressure (DLVP) and positive dP/dtmax (+dP/dtmax) was significantly higher in the Glutamate group than in the Control group during early reperfusion (DLVP: p < 0.05: +dP/dtmax: p < 0.01) and the entire reperfusion (DLVP and +dP/dtmax: p < 0.05), while reperfusion responses in the Glutamate and 30-min groups were not significantly different. Furthermore, myocardial oxygen uptake was significantly higher in the Glutamate group than in the Control group (p < 0.001), but not higher than that in the 30-min group. Decreased lactate release was found in the Glutamate group compared to the Control group during early reperfusion (p < 0.01), and the entire reperfusion (p < 0.001). No differences were found between the Control and Glutamate groups in alanine exchange. Thus, L-glutamate has a beneficial effect in pig hearts on both functional and metabolic recovery after cold crystalloid cardioplegia and storage when present in a concentration even as low as 2 mmol/L during continuous reperfusion after aortic unclamping. A possible mechanism is a glutamate-induced stimulation of the malate-aspartate shuttle leading to increased intramyocardial lactate utilization.

Thrombosis and intrinsic fibrinolysis in percutaneous transluminal angioplasty

Coagulation and fibrinolysis were investigated in 14 claudicants undergoing percutaneous transluminal angioplasty (PTA) for femoropopliteal artery lesions. Cross-linked fibrin degradation products (XL-FDP), tissue plasminogen activator (t-PA) antigen, fibrinopeptide A (FPA), and plasminogen activator inhibitor-1 (PAI-1) activity were measured in peripheral blood. XL-FDP and t-PA increased, and FPA and PAI-1 decreased significantly after angioplasty. XL-FDP increased from baseline 266 +/- 72 ng/ml to 481 +/- 239 ng/ml (p < 0.0005) 30 min after PTA, indicating mural thrombus formation in spite of the significant fall in FPA influenced by heparin. A groin haematoma developed after PTA in 4/6 patients, who received more than 5600 IU heparin and in 1/8 patients receiving smaller dosages. The alterations in PAI-1 showed no correlation with those of t-PA, whereas heparin had a sparing effect on PAI-1 consumption. These findings may indicate that PAI-1 acts as a thrombin inhibitor following deep vessel wall injury by angioplasty. In two patients, who had signs of rethrombosis on the next day, residual FPA was relatively high, XL-FDP peaked at 3530 +/- 1170 ng/ml, and t-PA increased by 2.6 +/- 1.0 ng/ml. The corresponding values in patients with an uncomplicated course were 406 +/- 89 ng/ml (p < 0.0001) and 0.1 +/- 0.5 ng/ml (p < 0.02). We conclude that thrombin promotes activation of coagulation and fibrinolysis in femoropopliteal PTA. Instability between these counteracting systems resulting in thrombosis is not prevented by conventional heparin administration at dosages causing bleeding complications.

Determination of high energy phosphates and glycogen in cardiac and skeletal muscle biopsies, with special reference to influence of biopsy technique and delayed freezing

OBJECTIVE

The aim was to clarify the influence of biopsy technique and the effects of temporal delay between sampling and freezing on tissue contents of labile metabolites.

METHODS

Cardiac and skeletal muscle concentrations of adenine nucleotides, phosphocreatine, creatine, and glycogen in pigs were determined in endomyocardial and transmural myocardial biopsies and in skeletal muscle biopsies obtained with either endomyocardial bioptome or Tru-cut needle. The influence of the temporal delay between biopsy sampling and freezing was evaluated by keeping the biopsies at room temperature for varying intervals up to 300 s before freezing.

RESULTS

Skeletal muscle showed higher concentrations of creatine compounds and lower contents of ADP and AMP than cardiac muscle, whereas ATP, total adenine nucleotide pool, and glycogen were similar. Lower phosphocreatine contents were found both in endomyocardial biopsies and in skeletal muscle biopsies obtained with bioptome compared to transmural myocardial biopsies and skeletal muscle biopsies obtained with Tru-cut needle, respectively. Other metabolites were unaffected by the biopsy technique. With extended delays between biopsy sampling and freezing, an increase in skeletal muscle phosphocreatine averaging 26% after 5 min was observed. In the heart, a decrease in glycogen content averaging 42% after 5 min was found. These changes were not related to the biopsy procedure and were not observed within the period usually required to freeze biopsies in experimental as well as clinical settings.

CONCLUSIONS

There are essential metabolic differences between cardiac and skeletal muscle. Low endomyocardial phosphocreatine levels are influenced by the biopsy technique, compromising the use of endomyocardial biopsies for establishing myocardial phosphocreatine content. Reliable measurements of adenine nucleotides and glycogen can be obtained with endomyocardial biopsies.

Analytical evaluation of high energy phosphate determination by high performance liquid chromatography in myocardial tissue

High performance liquid chromatography (HPLC) is an established method for the determination of myocardial high energy phosphates (HEP). Quantification of HEP compounds in small tissue specimens obtained by endomyocardial biopsy technique requires maximal sensitivity without impairment of precision. Employing isocratic ion-pair reversed-phase HPLC, high sensitivity and precision were obtained by running analyses for adenonucleotides and creatine compounds separately at detection wavelengths of 254 and 210 nm, respectively. Further reasons for separate runs were given by the necessity for different sample preparation as remaining perchloric ion after deproteinizing and pH in the samples had various effects on adenonucleotides and creatine compounds. Mechanical homogenization for 20 s in 0.42 mol/l perchloric acid ensured a consistent myocardial HEP extraction. Sample preparation directly following biopsy sampling is preferable since HEP compounds were labile in tissue within days at -80 degrees C even though an initial metabolic inhibition in liquid nitrogen had been induced. Following extraction and neutralization, HEP compounds were stable for up to 3 months at -20 degrees C.

Comparison of non-collagen protein and total creatine as reference for determination of energy stores in endomyocardial biopsies

OBJECTIVE

The aim was to establish a reliable reference system for biochemical measurements in endomyocardial biopsies.

METHODS

Myocardial tissue samples were obtained from pigs before and after cardioplegic arrest and reperfusion. Non-collagen protein content was evaluated as a non-specific reference system and compared with total creatine content representing a specific myocardial reference system. The influence of base strength, extraction temperature, and extraction time on protein yields was determined in tissue precipitates redissolved in NaOH. Interference from protein of collagenous origin was excluded by hydroxyproline determinations. Variability of myocardial ATP content in relation to non-collagen protein and total creatine was compared in endomyocardial biopsies taken before and after cardioplegic arrest and reperfusion.

RESULTS

The two methods showed comparable analytical precision. Apart from an interference in 1.0 mol.litre-1 NaOH for extended extraction periods at high temperatures, myocardial protein yields increased with increasing base strength, extraction temperature, and extraction time. During cardioplegic arrest and reperfusion heart weight increased due to oedema. Simultaneously, myocardial non-collagen protein content decreased. No change in total creatine was found during cardioplegic arrest but there was a significant loss of creatine after reperfusion. Comparison of variability in myocardial ATP content with non-collagen protein or total creatine as reference systems revealed no difference.

CONCLUSIONS

Determination of non-collagen protein can be optimised with standardised conditions for protein extraction in tissue precipitates. Employment of total creatine as a reference system does not reduce variability of myocardial metabolite determinations in endomyocardial biopsies compared with non-collagen protein. Loss of myocardial creatine may in itself provide additional information about myocardial injury but this makes it unsuitable as a reference system for measuring metabolic changes during reperfusion. Multiple biopsies seem necessary for estimation of myocardial energy stores.

Cross-linked fibrin degradation products (XL-FDP) as marker of early rethrombosis in percutaneous transluminal angioplasty

The thrombotic response to percutaneous transluminal angioplasty (PTA) was investigated in 31 patients treated for 1-10 cm femoropopliteal (n = 28) and tibial (n = 3) artery obstructions by measurement of cross-linked fibrin degradation products (XL-FDP) in peripheral blood samples drawn before and 30 min after PTA. XL-FDP increased from 400 +/- 147 ng/ml to 700 +/- 445 ng/ml (median +/- S.E., p = 0.0005). XL-FDP rose from 320 +/- 110 ng/ml to 540 +/- 102 ng/ml in 23 patients, whose ankle/brachial systolic blood pressure index (ABI) increased > 0.15 after PTA, whereas XL-FDP increased from 850 +/- 450 ng/ml to 2620 +/- 1472 ng/ml in eight patients, who failed to increase ABI in spite of preceding recanalisation. XL-FDP increased by more than 1000 ng/ml in 1/23 (4.3%) patients with uncomplicated PTA and in 6/8 (75%) patients with haemodynamic failure (p = 0.0005). Using a XL-FDP increase of 1000 ng/ml as cut-off, estimates of positive and negative predictive values (95% confidence limits) for early failure of PTA were 85.7% (42.1-99.6%) and 91.7% (73.0-99.0%), respectively. We conclude from this pilot study that femorotibial PTA produces a hypercoagulable state which may result in failure of early patency due to rethrombosis. We suggest for the first time XL-FDP as a marker of early rethrombosis in PTA, and report a sequential XL-FDP assay which may be useful for identification of high-risk patients requiring thrombolytic therapy after PTA for maintenance of early vascular patency.

Influence of pre-existing ischemia on recovery from chemical cardioplegia. A study on pig hearts in an isolated blood-perfused model

The impact of prior cardiac ischemia on recovery from chemical cardioplegia was investigated in pig hearts. Group I hearts were subjected to 9-min normothermic ischemia before the start of chemical cardioplegia. After 180 min of induced cardiac arrest, all hearts were reperfused and monitored for 120 min in a blood-perfused Langendorff model. Consistent with left ventricular performance, myocardial oxygen uptake was significantly lower in group I than in the other hearts during the first 60 min of reperfusion. Lactate elimination was significantly higher in group I at the start of reperfusion, but showed no intergroup difference after 25 min. Nor was intergroup difference found in left ventricular end-diastolic pressure, total myocardial flow or glucose extraction fraction during reperfusion. The mitochondrial ultrastructure was identical in the two groups before chemical cardioplegia. During cardioplegia it deteriorated in group I but normalized in group II. During reperfusion these circumstances were reversed. Although precardioplegic ischemia thus significantly impaired left ventricular performance during early recovery, with corresponding effects on metabolism and ultrastructure, stable performance during reperfusion indicated that the ischemic injury did not worsen.

Recovery after cold cardioplegic arrest of isolated blood-perfused hearts excised from non-anesthetized pigs

An isolated blood-perfused pig heart model has been established in order to evaluate the recovery of hearts obtained from slaughterhouse domestic pigs avoiding anesthesia and direct experiments on animals. Eleven hearts subjected to 9 min of normothermic ischemia were infused with cold modified Bretschneider solution. After 180 min of cardioplegic-induced global ischemia (including 9 min of normothermic ischemia) 8 hearts were reperfused for 120 min. Left ventricular function (measured isovolumetrically by means of a balloon, and expressed as developed left ventricular pressure, positive and negative dP/dt) was stable during the whole reperfusion period. Lactate production was abolished after 25 min of reperfusion, while there was a small glucose extraction during the whole reperfusion period. Slight deterioration of the mitochondria was found during the induced cardiac arrest, however, reversing during the reperfusion. Thus, due to the stability of left ventricular function, improved metabolism and ultrastructure during the reperfusion period, the model with no use of laboratory animals, and without any influence of anesthesia, seems to be suitable for testing the pure effect on the performance of the left ventricle of drugs and substrates added to the reperfusate during the reperfusion period.