Use Of Deep Hypothermic Circulatory Arrest Research Articles

Descending thoracic and thoracoabdominal aortic aneurysm repair using deep hypothermic circulatory arrest

Descending thoracic and thoracoabdominal aortic replacement is a complex and high-risk surgery. Deep hypothermic circulatory arrest (DHCA) is a surgical technique that is useful in large distal aortic arch aneurysms or chronic dissections that require fenestration where proximal cross clamping would be difficult. It can also be used as part of a multimodal strategy for end-organ protection. However, DHCA has potential adverse effects on the myocardial, cerebral, pulmonary, and coagulation systems. The use of DHCA is guided by the experience and preferences of the surgical team as well as the technical demands of the proposed surgery.

Postoperative Inflammation and Fever After Elective Aortic Valve and Aortic Root Replacement: A Retrospective Cohort Study.

Fever after cardiac surgery is common. More knowledge of postoperative fever could lead to better patient selection for diagnostic workup and empirical antibiotic treatment. We aimed to analyze the postoperative course of inflammation and fever after elective aortic valve and aortic root replacement. In a retrospective single-center cohort study, we included 3 groups of patients after elective cardiac surgery: aortic root with aortic valve replacement (Bentall procedure, from 2014 to 2021), valve-sparing root replacement (VSRR, from 2014 to 2021), and isolated surgical aortic valve replacement (SAVR, from 2018 to 2021). Exclusion criteria were age <18 years, cardiac surgery other than described, use of deep-hypothermic circulatory arrest, reoperations, and preexisting infections. Primary outcome measure was the number of patients per group with postoperative fever (≥38°C). Secondary outcome measures were the percentage of patients per group with infections and outcome. Among 307 patients included (76 Bentall, 40 VSRR, 191 SAVR), 71% had postoperative fever. Fever occurred significantly more often in the Bentall (84%) and VSRR group (83%) compared with patients after SAVR (64%, P = .001). Seventeen patients had fever due to infection versus 202 with diagnoses of postoperative inflammation. In case of infection, fever was significantly higher (38.8°C vs 38.4°C, P = .03), and both the number of days with fever and hospital admission duration were significantly longer. Postoperative fever is more often observed after Bentall procedure and VSRR compared to SAVR. In diagnoses of infection, there is a higher and prolonged fever.

IJU this issue

This issue contains two Review Articles, 11 Original Articles, three Urological Notes and five Editorial Comments. The number of people with diabetes rose rapidly. The prevalence in Japan is estimated to be approximately 10%. Sodium–glucose-linked transport protein 2 (SGLT2) inhibitors are newly developed drugs, used for the treatment of type 2 diabetes mellitus, that act on the proximal convoluted tubules of the nephrons to prevent resorption of glucose from the filtrate. In this issue Chandrashekar et al. (Brisbane, Australia) reviewed the urological implications of these drugs. Increased glycosuria is thought to result in genital infections and urinary tract infections. Genital infections in males, which can be increased by up to fivefold, include balanitis and balanoposthitis. SGLT2 inhibitors might also cause Fournier’s gangrene. Unexpectedly, one large-scale study failed to show the increased risk for severe and non-severe urinary tract infection events among cases treated with SGLT2 inhibitor, compared with those among cases treated with dipeptidyl peptidase-4 inhibitors or glucagon-like peptide-1 agonists. Pollakiuria and nocturia, which might have impacts on quality of life, were the most prevalent lower urinary tract symptoms after initiation of SGLT2 inhibitors. Notably, the authors recommended that SGLT2 inhibitors should be ceased perioperatively, because perioperative use increases the risk of euglycemic diabetic ketoacidosis. Three original articles and one urological note on renal cell carcinoma (RCC) appear in this issue. Ishiyama et al. (Tokyo, Japan) reviewed their 23 patients who underwent extracorporeal circulation-assisted surgery with or without using deep hypothermic circulatory arrest (DHCA). They found that surgical time, estimated blood loss, perioperative complication rate, 90-day mortality rate and hospital stay days were similar between these two groups. In addition, oncological outcomes (cancer-specific and overall survival) did not differ between groups. They concluded that the use of DHCA did not result in inferior perioperative outcomes. Although DHCA often requires longer operative time and are thought to be related with platelet dysfunction and coagulopathy, the authors successfully showed the safety and usefulness of DHCA. Wakita et al. (Kobe, Japan) reported on the surgical outcomes of the complex tumors of the kidney treated with robot-assisted partial nephrectomy (RAPN). They retrospectively analyzed 348 patients who underwent RAPN at a single center; 299 had non-complex tumors (RENAL score <10) and 49 had complex tumors (RENAL score ≥10). Although more perioperative complications and lower postoperative renal function with longer ischemia time and console time were observed in the complex tumors group, positive surgical margin rate and recurrence-free survival did not differ between groups. They concluded that RAPN for complex renal tumors is safe, with no difference in oncological outcomes despite more complications and decreased renal function. For the complex tumors, radical nephrectomy or open partial nephrectomy tend to be carried out, even in this era. The authors clearly showed the effectiveness and safety, along with limitation, of RAPN for the complex tumors. Several risk factors for recurrence or survival in pT3a RCC patients have been proposed. In this issue Ohsugi et al. (Hirakata, Japan) performed a retrospective study assessing the predictors of postoperative recurrence in non-metastatic patients with pT3a RCC. Analyzing 114 patients, they identified three predictors for recurrence-free survival on multivariate analysis, perinephric fat invasion, sarcomatoid or rhabdoid features and necrosis. They found that high-risk pT3a cases with two or three of these predictors had poor prognosis, and that the recurrence-free survival was similar between high-risk pT3a cases and those with pT3b or greater. Previously, the impact of perinephric fat invasion on cancer-specific survival was analyzed using 2998 patients from the RCC registry of The Cancer Registration Committee of JUA.1 Perinephric fat invasion was associated with advanced age and aggressive pathological features, and was an independent prognostic factor in non-metastatic RCC especially in larger tumors. Nivolumab plus ipilimumab is widely used for the first-line therapy for advanced RCC. Ishihara et al. (Tokyo, Japan) reviewed their 16 advanced RCC cases without prior nephrectomy. They found that tumor response between primary and metastatic lesions was generally parallel. Interestingly, the magnitude of tumor response ranged more widely in metastatic lesions than in primary lesions. As unresectable RCC is not rare, this study provides us useful clinical information on decision-making. None declared.

Neuroprotective strategies in acute aortic dissection: an analysis of the UK National Adult Cardiac Surgical Audit.

OBJECTIVESThe risk of brain injury following surgery for type A aortic dissection (TAAD) remains substantial and no consensus has still been reached on which neuroprotective technique should be preferred. We aimed to investigate the association between neuroprotective strategies and clinical outcomes following TAAD repair.METHODSUsing the UK National Adult Cardiac Surgical Audit, we identified 1929 patients undergoing surgery for TAAD (2011–2018). Deep hypothermic circulatory arrest (DHCA) only, unilateral (uACP), bilateral antegrade cerebral perfusion (bACP) and retrograde cerebral perfusion were used in 830, 117, 760 and 222 patients, respectively. The primary end point was a composite of death and/or cerebrovascular accident (CVA). Generalized linear mixed model was used to adjust the effect of neuroprotective strategies for other confounders.RESULTSThe use of bACP was associated with longer circulatory arrest (CA) compared to other strategies. There was a trend towards lower incidence of death and/or CVA using uACP only for shorter CA. In particular, primary end point rate was 27.7% overall and 26.5%, 12.5%, 28.0% and 22.9% for CA <30 min and 28.6%, 30.4%, 33.3% and 33.0% for CA ≥30 min with DHCA only, uACP, bACP and retrograde cerebral perfusion, respectively. The use of DHCA only was associated with five-fold [odds ratio (OR) 5.35, 95% confidence interval (CI) 1.36–21.02] and two-fold (OR 1.77, 95% CI 1.01–3.09) increased risk of death and/or CVA compared to uACP and bACP, respectively, but the effect of uACP was significantly associated with CA duration (hazard ratio 0.97, 95% CI 0.94–0.99; P = 0.04).CONCLUSIONSIn TAAD repair, the use of uACP and bACP was associated with a lower adjusted risk of death and/or CVA when compared to DHCA. uACP can offer some advantage but only for a shorter CA duration.

The role of deep hypothermic circulatory arrest in surgery for renal or adrenal tumor with vena cava thrombus: a single-institution experience

BackgroundThe aim of this study was to review our experience in managing renal or adrenal tumors with level III or IV inferior vena cava thrombus by using deep hypothermic circulatory arrest (DHCA), and to evaluate survival outcomes.MethodsBetween September 2004 and March 2016, we treated 33 patients with renal or adrenal malignancy tumor and thrombus extending into the inferior vena cava. Patients were identified according to radiographic records and operative findings. Clinicopathological and operative characteristics were recorded, and comparisons of clinical and operative characteristics through DHCA were performed. A Cox regression model was used to determine predictors of perioperative mortality.ResultsTwenty-one out of 33 patients with level III (n = 15), level IV (n = 5), or level II (n = 1) renal or adrenal tumors were treated surgically through cardiopulmonary bypass (CPB) with DHCA, and 12 patients with level II or III tumors were treated surgically through normothermic CPB. Three complications were observed, and one death occurred perioperatively, owing to multiple organ failure. The overall perioperative mortality was 4.7%. There were significant differences in the clinicopathological characteristics, operative duration, estimated blood loss, transfusions and hospital stay depending on use of DHCA. Multivariate analysis indicated that the operative duration (OR, 3.78; P < 0.001), estimated blood loss (OR, 1.08; P = 0.02), and transfusion (OR, 2.13; P = 0.038) during/after surgery were positively associated with higher mortality and morbidity. DHCA failed to reach statistical significance (P = 0.378).ConclusionsUse of CPB and DHCA to treat renal or adrenal tumors allows for complete tumor resection, especially at the T4 stage. Although it can cause physical damage, this technique does not increase operative risk and is a relatively safe approach.

Hemiarch Reconstruction Versus Clamped Aortic Anastomosis for Concomitant Ascending Aortic Aneurysm

Deep hypothermic circulatory arrest (DHCA) is often avoided in patients with concomitant ascending aortic pathology when treating another cardiac disease to avoid increased risk of morbidity and mortality. We hypothesized that the use of DHCA with retrograde cerebral perfusion (RCP) does not add incremental risk to ascending aortic replacement alone in the setting of concomitant cardiac surgery. A total of 408 ascending aortic ± hemiarch replacements and aortic (root), mitral, or tricuspid valve(s); coronary artery bypass grafting; or MAZE procedures were performed for concomitant cardiac disease. DHCA with RCP was used for all hemiarch replacements or the ascending aorta was replaced with an aortic cross-clamp proximal to the innominate artery. Propensity score matching was used to match similar ascending aorta patients versus hemiarch patients; the final propensity score-matched patients on age, sex, body mass index, previous heart surgery, preoperative aortic insufficiency, preoperative aortic stenosis, preoperative ejection fraction, and operative variables. Propensity score matching yielded 116 pairs of non-hemiarch patients versus 116 hemiarch patients. Within the propensity score-matched cohort, there were no differences in postoperative stroke (1.7% versus 3.4%; p= 0.41), new postoperative dialysis (6.0% versus 5.2%; p= 0.78), postoperative renal insufficiency (27.6% versus 19.8%; p= 0.16), 30-day mortality (2.6% versus 3.4%; p= 0.701), or 1-year mortality (4.3% versus 4.3%; p= 1.00) CONCLUSIONS: Hemiarch replacement using DHCA with RCP does not increase the risk of operative complications compared with a normothermic, clamped-distal aortic anastomosis, and therefore its use should not be limited when planning complex multiprocedural reconstructions during elective ascending thoracic aortic replacement with concomitant cardiac surgery.

Successful use of deep hypothermic circulatory arrest (DHCA) during mid-term pregnancy

Introduction Ascending aortic dissection (Type A) often requires deep hypothermic circulatory arrest (DHCA) for proper repair. It involves the use of cardiopulmonary bypass to achieve whole body cooling to a temperature of 18 degrees Celsius prior to the cessation of all circulation. This circulatory arrest then allows for repair of the aortic arch and/or cerebral vessels without cross-clamp. This technique is well described and has become standard practice in the treatment of Type A dissection. The use of DHCA during pregnancy, however, has seldom been described. Case description A 31-year-old female at 21 weeks gestation presented acutely to the emergency department with a Type A aortic dissection. She was taken emergently to the operating room and cardiopulmonary bypass was initiated via femoral arterial and central venous cannulation. Aortic repair was accomplished during a 25 minute period of DHCA. Destruction of her aortic root by the dissection included the right coronary ostium and required composite tissue valve and conduit replacement (Bio–Bentall) with right coronary saphenous vein bypass. Fetal ultrasound imaging obtained preoperatively and postoperatively demonstrated no changes in fetal heart tones or obvious evidence of fetal injury. She was subsequently discharged on postoperative day 4. Evaluation by obstetrics 8 weeks postoperatively (29 weeks gestation) revealed normal fetal growth. 4 months post operatively she delivered a full-term infant without any noticeable deficits. Conclusions The use of DHCA for type A aortic dissection is standard practice but its use during pregnancy has rarely been described. This case illustrates the use of DHCA during midterm pregnancy that resulted in an excellent outcome. Take home message DHCA can successfully be used during midterm pregnancy.

Variation in Perfusion Strategies for Neonatal and Infant Aortic Arch Repair: Contemporary Practice in the STS Congenital Heart Surgery Database.

Regional cerebral perfusion (RCP) is used as an adjunct or alternative to deep hypothermic circulatory arrest (DHCA) for neonates and infants undergoing aortic arch repair. Clinical studies have not demonstrated clear superiority of either strategy, and multicenter data regarding current use of these strategies are lacking. We sought to describe the variability in contemporary practice patterns for use of these techniques. The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2013) was queried to identify neonates and infants whose index operation involved aortic arch repair with cardiopulmonary bypass. Perfusion strategy was classified as isolated DHCA, RCP (with less than or equal to ten minutes of DHCA), or mixed (RCP with more than ten minutes of DHCA). Data were analyzed for the entire cohort and stratified by operation subgroups. Overall, 4,523 patients (105 centers) were identified; median age seven days (interquartile range: 5.0-13.0). The most prevalent perfusion strategy was RCP (43%). Deep hypothermic circulatory arrest and mixed perfusion accounted for 32% and 16% of cases, respectively. In all, 59% of operations involved some period of RCP. Regional cerebral perfusion was the most prevalent perfusion strategy for each operation subgroup. Neither age nor weight was associated with perfusion strategy, but reoperations were less likely to use RCP (31% vs 45%, P < .001). The combined duration of RCP and DHCA in the RCP group was longer than the DHCA time in the DHCA group (45 vs 36 minutes, P < .001). There is considerable variability in practice regarding perfusion strategies for arch repair in neonates and infants. In contemporary practice, RCP is the most prevalent perfusion strategy for these procedures. Use of DHCA is also common. Further investigation is warranted to ascertain possible relative merits of the various perfusion techniques.

Prolonged postoperative respiratory support after proximal thoracic aortic surgery: Is deep hypothermic circulatory arrest a risk factor?

PurposeIn addition to the pulmonary risks associated with cardiopulmonary bypass, thoracic aortic surgery using deep hypothermic circulatory arrest (DHCA) may subject the lungs to further injury. However, this topic has received little investigation to date. Materials and MethodsA prospective cohort review was performed on all patients undergoing proximal thoracic aortic surgery with (n = 478) and without (n = 135) DHCA between July 2005 and February 2013 at a single institution. The primary outcome was prolonged postoperative respiratory support (PPRS), defined as any of the following: >1 day of mechanical ventilation at either fraction of inspired oxygen >0.4 and/or positive end-expiratory pressure >5 mm Hg, >2 days of supplemental O2 requirement of at least 2.5 L/min, or discharge with new O2 requirement. Independent risk factors for PPRS were identified using multivariable logistic regression. ResultsPostoperative respiratory support was required in 100 patients (20.9%) with and 30 patients (22.2%) without DHCA (P = .74). Independent predictors of PPRS after proximal aortic surgery included the following: age, diabetes, history of stroke, preoperative creatinine, American Society of Anesthesiologists class 4, redo-sternotomy, total arch replacement, and transfusion requirement. Use of DHCA was not an independent risk factor for PPRS in the entire cohort. Subanalysis of only DHCA patients revealed that longer DHCA times were independently associated with PPRS. ConclusionsProlonged postoperative respiratory support is common after proximal aortic surgery. The use of DHCA was not associated with this complication in the overall cohort, although longer DHCA times were predictive when only the subset of patients undergoing DHCA was analyzed. Knowledge of the risk factors for PPRS after proximal aortic surgery should improve preoperative risk stratification and postoperative management of these patients.

Cardiopulmonary bypass and renal cell carcinoma with level IV tumour thrombus: can deep hypothermic circulatory arrest limit perioperative mortality?

• To review experience with nephrectomy/thrombectomy for a renal cell carcimoma (RCC) with a level IV tumour thrombus and to evaluate the benefit of deep hypothermic circulatory arrest (DHCA) with cardiopulmonary bypass (CPBP). • A multi-institutional retrospective database was created to assess the outcomes of surgery for RCC and associated level IV tumour thrombus from 1983 to 2007. Patients were identified based on radiographic records/operative findings. • Only cases using CPBP were analysed. Clinicopathological and operative characteristics including use of DHCA were recorded. • Overall survival (OS) for all patients and by use of DHCA was assessed. Comparisons of clinical and operative characteristics by use of DHCA were performed. • A Cox regression model determined predictors of perioperative/in-hospital mortality. • In all, 63 patients underwent resection with CPBP; overall perioperative mortality was 22.2%. • There were no significant differences in clinicopathological characteristics, operative duration, estimated blood loss, transfusions, and hospital stay by use of DHCA. • Perioperative mortality rate was lower in patients undergoing DHCA (8.3% vs 37.5%, P = 0.006). • The median OS was longer for the patients undergoing DHCA (15.8 vs 7.7 months); however, this failed to reach statistical significance (P = 0.357). • On multivariate analysis, age of > 60 years (hazard ratio [HR] 6.7, 95% confidence interval [CI] 1.5-31.1, P = 0.015) and the use of DHCA (HR 0.13, 95% CI 0.036-0.51, P = 0.003) were independent predictors of perioperative mortality. • Radical nephrectomy and level IV tumour thrombectomy is associated with significant mortality. • The use of DHCA does not appear to adversely affect operative characteristics and may limit perioperative mortality. • Further prospective studies should be performed to confirm the benefit of DHCA.

Deep Hypothermic circulatory arrest does not impair neurodevelopmental outcome in school-age children after infant cardiac surgery

The purpose of this study was to assess deep hypothermic circulatory arrest (DHCA) as a modifier of neurodevelopmental (ND) outcomes in preschool children after cardiac surgery in infancy for repair of congenital heart defects (CHD). This is a planned analysis of infants enrolled in a prospective study of apolipoprotein E polymorphisms and ND outcome after cardiac surgery. The effect of DHCA was assessed in patients with single or biventricular CHD without aortic arch obstruction. Neurodevelopmental assessment at 4 years of age included cognition, language, attention, impulsivity, executive function, social competence, and visual-motor and fine-motor skills. Patient and procedural variables were evaluated in univariate and multivariate models. Neurodevelopmental testing was completed in 238 of 307 eligible patients (78%). Deep hypothermic circulatory arrest was used at the discretion of the surgeon at least once in 92 infants (38.6%) with a median cumulative duration of 36 minutes (range, 1 to 132 minutes). By univariate analysis, DHCA patients were more likely to have single-ventricle CHD (p = 0.013), lower socioeconomic status (p < 0.001), a higher incidence of preoperative ventilation (p < 0.001), and were younger and smaller at the first surgery (p < 0.001). By multivariate analysis, use of DHCA was not predictive of worse performance for any ND outcome. In this cohort of children undergoing repair of CHD in infancy, patients who underwent DHCA had risk factors associated with worse ND outcomes. Despite these, use of DHCA for repair of single-ventricle and biventricular CHD without aortic arch obstruction was not predictive of worse performance for any ND domain tested at 4 years of age.

Anesthetic Management for the Pediatric Patient Undergoing Deep Hypothermic Circulatory Arrest

Early definitive repair of complex congenital heart defects is now advocated. For the completion of many of these repairs, the use of deep hypothermic circulatory arrest (DHCA) is an absolute necessity. Unfortunately, there is undeniable neurologic morbidity, as well as other complications associated with DHCA. Anesthesiologists can aid in minimizing these unfortunate complications with the appropriate anesthetic management. Areas of current controversy in managing pediatric patients undergoing DHCA, which will be covered in this article, include cardiopulmonary bypass strategies (low-flow cardiopulmonary bypass versus DHCA), arterial blood gas management, hemodilution effects, glucose management, and the use of steroids, barbiturates, and antifibrinolytics. Every institution varies in their techniques, and there is always some new insight to be gained from discussion of these differences. At this time, anesthesiologists and surgeons alike are striving to gain further understanding of what truly occurs with the use of DHCA and in turn apply this clinically to provide better care for all pediatric patients undergoing this unique management.

Hypoxemic reperfusion exacerbates the neurological injury sustained during neonatal deep hypothermic circulatory arrest: a model of cyanotic surgical repair☆

Deep hypothermic circulatory arrest (DHCA) is frequently used in infants undergoing the Norwood procedure. These infants are necessarily hypoxemic after separation from CPB. Considerable energy has been spent characterizing the physiological and histological consequences of DHCA, but these have largely focused on a normoxemic period of reperfusion. Furthermore, evidence has accumulated to suggest that the cerebral vascular autoregulatory mechanisms are dysfunctional following DHCA. In particular, the vasodilatation that elevates cerebral blood flow (CBF) in response to hypoxemia is absent. This study therefore aimed to investigate whether post-CPB hypoxemia exacerbates brain injury resulting from DHCA. Twelve neonatal piglets were subjected to 2h DHCA and then separated from CPB. They were then randomized to either: Group 1, normoxic ventilation (n=5); or Group 2, hypoxemia (n=7), in which the arterial PaO(2) was reduced to 40-50 mmHg for the duration of reperfusion. Following a 20 h period of warm reperfusion, the animals were perfusion fixed and the brain analyzed for histological evidence of injury. Nine additional animals were studied in one of three control groups. All animals survived the protocol. Post-operative parameters - including mean arterial pressure, acid-base status, inotrope requirements and arterial PaCO(2) - were similar. None of the control animals had any evidence of ischemia. Group 1 animals had moderate injury (total score 7.4+/-1.6). In Group 2, three animals sustained irretrievable brain injury evidenced by gross edema and early liquefactive necrosis. The remaining four had severe ischemic histological changes (score 14.5+/-1.6, p<0.03). Hypoxemic reperfusion after prolonged DHCA results in increased neuronal loss. The use of DHCA for staged palliation may confer disproportionately greater cerebral risk than other patient groups. Alternatively, methods to augment oxygen delivery - such as by ECMO - may be of particular benefit in the early re-perfusion window.

Effects of deep hypothermic circulatory arrest on outcome after resection of ascending aortic aneurysm

Background. Aneurysm of the ascending aorta is a common finding especially in patients with aortic valve diseases. The aim of this study was to analyze early and midterm outcome in patients operated on for aneurysm of the ascending aorta with or without the use of deep hypothermic circulatory arrest (DHCA). Methods. Between January 1996 and December 2000, 133 of 410 patients with thoracic aortic pathology were operated on for an aortic aneurysm limited mainly to the ascending aorta. Early and midterm outcomes were assessed and quality of life (QOL) evaluated using the Short-Form 36 Health Survey Questionnaire (SF-36). Results. Sixty patients (group 1) were operated on with DHCA and 73 patients (group 2) without DHCA. In-hospital mortality was identical in both groups (9.6% versus 6.7%; p = not significant) whereas postoperative transient neurologic events were significantly more frequent in group 1 (6.7% versus 0%; p < 0.05). Midterm clinical outcome was not different between groups but QOL showed significant impairment in daily functional physical and emotional activity in group 1 patients compared with group 2 and an age-matched standard population. Conclusions. The risk of transient neurologic complications is significantly increased with the use of DHCA and QOL is impaired without benefits in the long-term outcome especially among older patients.

Invited commentary

Invited commentary

Preoperative high dose methylprednisolone attenuates the cerebral response to deep hypothermic circulatory arrest.

The aim of this study was to assess the effects of preoperative high dose methylprednisolone on cerebral recovery following a period of deep hypothermic circulatory arrest (DHCA). Sixteen 1-week-old piglets were randomized to placebo (n=8), or 30 mg/kg intramuscular methylprednisolone sodium succinate (MPRED) given at 8 and 2 h before induction of anaesthesia. All piglets underwent cardiopulmonary bypass, cooling to 18 degrees C, 60 min of circulatory arrest followed by 60 min of reperfusion and rewarming. The radiolabelled microsphere method was used to determine the global and regional cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO(2)) at baseline before DHCA and after 60 min of reperfusion. In controls, mean global CBF (+/-1 standard error) before DHCA was 53.7+/-2.4 ml/100 g per min and fell to 23.8+/-1.2 ml/100 g per min following DHCA (P<0.0001). This represents a post-DHCA recovery to 45.1+/-3.3% of the pre-DHCA value. In the MPRED group recovery of global CBF post-DHCA was significantly higher at 63.6+/-5.2% of the pre-DHCA value (P=0.009). The regional recovery of CBF in the cerebellum, brainstem and basal ganglia was 80, 75 and 69% of pre-DHCA values in the MPRED group respectively compared to 66, 60 and 55% in controls (P<0.05). Global CMRO(2) in controls fell from 3.9+/-0.2 ml/100 g per min before to 2. 3+/-0.2 ml/100 g per min after DHCA (P=0.0001). This represents a post-DHCA recovery to 58.6+/-4.4% of the pre-DHCA value. In the MPRED group, however, recovery of global CMRO(2) post-DHCA was significantly higher at 77.9+/-7.1% of the pre-DHCA value (P=0.04). Treatment with high dose methylprednisolone at 8 and 2 h preoperatively attenuates the normal cerebral response to a period of deep hypothermic ischaemia. This technique may therefore offer a safe and inexpensive strategy for cerebral protection during repair of congenital heart defects with the use of DHCA.

Pro: Deep hypothermic circulatory arrest is preferable to low-flow bypass

ORTALITY RATES in infants undergoing cardiopulmonary bypass (CPB) for repair of complex congenital heart disease were unacceptably high until deep hypothermic circulatory arrest (DHCA) techniques began to be used extensively in the 1970s. During this time, there was a great deal of morbidity related to CPB in infants and an appreciable mortality. In several studies, mortality and morbidity in infants having cardiac operations using CPB were inversely related to the age and size of the child; younger and smaller children had more problems, especially in the infant age group.’ Although this may have been related in part to the severity of disease observed in young infants, activation of complement was greater in small infants; longer CPB times were directly related to the morbidity of CPB.’ Use of DHCA eliminated much CPB time, minimizing morbidity and dramatically improving mortality in small children undergoing cardiac surgical procedures. The mechanisms of CPB-related damage and morbidity are not yet well understood, particularly in the infant. However, cardiac morbidity related to inadequate myocardial protection during ischemia is decreased by using deep, whole-body hypothermia and circulatory arrest. With deep hypothermia there is less conductive heat transfer to the heart from the warmer surrounding tissues, and with circulatory arrest, washout of cardioplegia and cardiac rewarming by noncoronary collateral circulation does not occur. Given the dubious value of many cardioplegic solutions in the immature heart, improved myocardial protection with DHCA is an important consideration, particularly in defects such as hypoplastic left heart syndrome (HLHS), in which the use of conventional aortic root cardioplegia is technically impractical. Improvements in the technology of CPB and general care of infants with congenital heart disease have considerably lessened CPB-related morbidity and mortality in young cardiac patients. Although these developments make the rationale for use of DHCA less convincing, CPB-related morbidity remains a considerable problem in infants undergoing cardiac sur

Experience with Cardiopulmonary Bypass and Deep Hypothermic Circulatory Arrest in the Management of Retroperitoneal Tumors with Large Vena Caval Thrombi

From June 1984 to September 1989, 43 patients with large vena caval tumor thrombi from retroperitoneal malignancies underwent surgical treatment with cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). The primary malignancies were renal cell carcinoma (RCC) (n = 39), renal pelvic transitional cell carcinoma (n = 1), adrenal pheochromocytoma (n = 1), and renal (n = 1) or retroperitoneal (n = 1) sarcoma. The level of the caval thrombus was either suprahepatic (n = 27), intrahepatic (n = 14), or subhepatic (n = 2). In all cases the primary tumor and caval thrombus were completely removed. Concomitant procedures included coronary artery bypass grafting (n = 5), pulmonary resection (n = 2), and hepatic lobectomy (n = 1). The time of circulatory arrest ranged from 10 to 44 minutes (mean, 23.5 minutes). There were two operative deaths (4.7%), neither of them due to to the use of DHCA. Major postoperative complications occurred in 13 patients (30.2%). There were no ischemic or neurologic complications and no cases of perioperative tumor embolization. The median postoperative hospital stay was 9 days. Twenty-two patients (51%) are alive and enjoying a good quality of life. The 3-year patient survival rates in patients with localized (n = 24) versus metastatic (n = 15) RCC are 63.9% and 10.9%, respectively (p = 0.02). We conclude that CPB with DHCA facilities excision of retroperitoneal malignancies with large caval thrombi and provides the potential for cure with low morbidity and mortality rates.