Coronary artery bypass grafting with cardiopulmonary bypass versus off-pump cardiopulmonary bypass grafting: does eliminating the pump reduce morbidity and cost?

BACKGROUND: Cardiopulmonary bypass (CPB) may contribute to the complications and cost of coronary artery bypass grafting (CABG). Off-pump CABG (OPCAB) allows coronary revascularization without CPB. We hypothesized that OPCAB provides satisfactory graft patency while reducing complications and cost compared with CABG with CPB. METHODS: We prospectively followed 80 patients undergoing CABG: 40 patients undergoing OPCAB and 40 patients undergoing CABG with CPB. OPCAB patients underwent angiography within 48 hours of surgery to determine early graft patency. Incidence of complications, length of stay, and costs were recorded for each patient. The influence of the number of vessels bypassed was analyzed. RESULTS: OPCAB patients (n = 40) underwent grafting of 2.7 +/- 0.7 vessels per patient compared with 3.6 +/- 0.8 vessels per patient in the CABG with CPB group (n = 40) (p < 0.0001). Angiography demonstrated 105 of 108 (97%) of grafts were patent in the OPCAB group. Incidence of complications, length of stay, and costs did not differ between the OPCAB and CABG with CPB groups. Number of vessels grafted showed a positive correlation to total costs in both groups. CONCLUSIONS: While OPCAB provided satisfactory early graft patency, there was no significant difference between OPCAB and CABG with CPB with regard to cost, length of stay, or incidence of complications. In this study, eliminating CPB did not reduce morbidity or cost after CABG.     

Are peroneal artery bypass grafts hemodynamically inferior to other tibial artery bypass grafts?

Purpose: Many authors have reported excellent long-term patency rates of peroneal artery bypasses. It has been suggested, however, that the hemodynamic result of the peroneal bypass is inferior to that of other infrapopliteal artery bypasses, making it suboptimal in patients with forefoot ischemic tissue loss. A retrospective review of 118 recent infrainguinal vein grafts (36 peroneal, 27 anterior tibial, 35 posterior tibial, 20 popliteal) was undertaken to assess and compare the hemodynamic results for each group.Methods: We reviewed the hemodynamic results of 36 peroneal bypass grafts assessed by preoperative and postoperative ankle-brachial index and transmetatarsal pulse volume recording, duplex scan-derived distal graft peak systolic flow velocity, and intraoperatively measured outflow resistance. These results were compared with a concurrent series of anterior tibial, posterior tibial, and popliteal artery bypass grafts. All but one of the infrapopliteal bypass grafts were performed for limb salvage, and 65% of patients had ischemic ulcerations or gangrene.Results: There was no difference in postoperative ankle-brachial index, postoperative transmetatarsal pulse volume recording, peak systolic flow velocity, or measured outflow resistance among the four different outflow groups. All patients with peroneal bypass grafts had healed wounds within a mean follow-up period of 17 months. There were no hemodynamic failures.Conclusion: Peroneal artery bypass grafts achieved hemodynamic results equivalent to anterior tibial, posterior tibial, and popliteal artery bypass grafts. (J VASC SURG 1994;19:964–9.)     

Is above knee bypass defunct?

As endovascular treatments improve, the inevitable progress will result in the abandonment of conventional bypasses. First and foremost in this regard is the use of above knee bypass, particularly with prosthetic graft material. Already, endovascular success approaches or exceeds the patency seen with this bypass technique. As a result, in centers with endovascular expertise in infrainguinal intervention, bypass surgery is increasingly being replaced by these techniques and conventional bypass surgery is disappearing. Over the next few years, above knee bypass will be replaced by endovascular techniques in most centers as our results with these techniques improve.     

Is median sternotomy invasive? A comparison between minimally invasive direct coronary artery bypass and off-pump bypass

vs 66 ± 8 years old, the operative time, being 321 ± 149 vs 441 ± 205 min, the number of grafts, being 1.0 vs 1.4/patient, peak creatine kinase (CK) values, being 662 ± 436 vs 609 ± 56 IU/l, the peak CK-muscle-brain values, being 12 ± 9 vs 16 ± 5 IU/l, and the postoperative blood loss, being 369 ± 198 vs 541 ± 204 ml. Although there was no significant difference in peak C-reactive protein, at 17 ± 5 vs 20 ± 2 mg/dl, the periods declining within the normal ranges were shorter in the MIDCAB group than in the off-pump group, at 7 ± 1 vs 15 ± 2 days (P > 0.01). The hospital stay was almost the same in both groups, at 16 ± 8 vs 26 ± 14 days. These findings suggest that off-pump bypass is more invasive than MIDCAB, which may be attributed to the median sternotomy. (Received for publication on May 6, 1999; accepted on Jan. 12, 2000)     

Concomitant carotid endarterectomy and coronary bypass surgery: should cardiopulmonary bypass be used for the carotid procedure?

BACKGROUND AND OBJECTIVES: With the increasing age of patients undergoing coronary artery bypass grafting (CABG), a greater number have associated clinically significant carotid disease. This study determined the morbidity and mortality for combined carotid endarterectomy (CEA)/CABG using cardiopulmonary bypass (CPB) for both procedures versus a combined approach using CPB only during CABG. PATIENTS AND METHODS: Between 1993 and 2000, 65 patients (Group I) underwent combined CEA and CABG using CPB for both surgical procedures and 88 patients (Group II) underwent combined CEA and CABG using CPB only during CABG. The demographic, clinical, and carotid and coronary angiographic data were similar between groups. In Group I, 22 (33.8%) patients and 32 (36%) patients in Group II presented with contralateral carotid artery stenosis. RESULTS: CPB time was significantly longer in Group I, 127+/-21 minutes versus 98+/-11 minutes in Group II patients (p = 0.001). The incidence of surgical revision for bleeding and deep sternal wound infection was higher in Group I patients, 2 (3%) versus 1 (1.1%) and 5 (7.7%) versus 2 (2.2%), respectively, but not significant. Hospital mortality in Group I was 6% (4 patients) versus 5.7% (5 patients) in Group II (p = ns). Neurologic complications occurred in 4 (6%) and 5 (5.7%) patients in Group I and II, respectively (p = ns). Postoperative renal dysfunction was more common in Group I patients (22 [33.8%]) then in Group II patients 16 (19%) (p = 0.04). Of these patients, (16 [19%]) 8 (12.3%) in Group I and 6 (6.8%) in Group II required postoperative ultrafiltration (p = ns). Infectious complications were more frequent in Group I patients, 5 (7.7%) versus 2 (2.3%), but not statistically significant (p = ns). Overall actuarial survival at 1, 3, and 5 years, including all deaths, was 92%, 88%, and 82% in Group I versus 93%, 86%, and 81% in Group II (p = ns). Overall freedom from stroke at 5 years was 87.5% in Group I and 86.4% in Group II. CONCLUSIONS: We conclude that combined CEA/CABG using CPB only during the myocardial revascularization procedure remains the technique of choice in patients with coronary and carotid artery disease, offering better outcome in terms of perioperative morbidity than a combined CEA/CABG using CPB for both procedures.     

Pumphead--or not! Does avoiding cardiopulmonary bypass for coronary artery bypass surgery result in less brain damage?

Symptomatic benefit aside, coronary artery bypass grafting (CABG)surgery has prognostic advantages. Every day around the world,and despite the inexorable rise in the use of angioplasty, manythousands of patients still have patterns of coronary arterydisease that require them to undergo CABG surgery to improvetheir longevity. However, this success of CABG surgery continuesto be marred by a number of serious complications, in particularbrain damage. The most overt manifestation of brain damage is stroke, whichfortunately, given its impact on quality of life, occurs infrequently,in 3% of patients.¹ If looked for prospectively, more subtleneurological deficits occur far more frequently, in 20% of patients.²³ Cognitive decrements are another manifestation; 19–26%of patients undergoing conventional CABG surgery will experiencepermanent decrements and the incidence increases with increasingage.^3–5 These decrements are important as they affectmemory,     

The masaryk hospital extracranial–intracranial bypass study

Patients with symptomatic internal carotid artery (ICA) occlusion with haemodynamic impairment are at higher risk of ischaemic stroke, and they require treatment. There are two main options: the best medical treatment and an extracranial–intracranial bypass. The aims of this study are to analyse the 30-day and 2-year risk of stroke and death in patients with extracranial–intracranial bypass performed by our department and to compare our results with major published studies. This retrospective study enrolled patients who underwent surgery from 1998 to 2012. Inclusion criteria were the following: (1) radiological diagnosis of symptomatic atherosclerotic internal carotid artery occlusion (AICAO), (2) less than 50 % stenosis of a contralateral ICA, (3) transient ischaemic attack (TIA) or ischaemic stroke in the hemispheric territory on an occluded side within 120 days and (4) haemodynamic impairment of at least stage I according to transcranial Doppler sonography (TCDS), perfusion CT and SPECT. Patients were followed up in the outpatient department with TCDS and sonography of the contralateral ICA and the anastomosis after 6 weeks and every 12 months after that. All risks of stroke and death from surgery were recorded throughout the 30 days and the following 2 years post surgery. From September 1998 to November 2012, 93 patients were selected for bypass surgery. There were 72 men and 21 women in an age range of 33 to 79 years (mean 58.9 years) and a follow-up range of 13 to 187 months (mean 108 months). The 30-day risk of stroke and death was 7.5 %. It consists of one death, one major ischaemic stroke, two reversible neurological deficits and three TIAs. The 2-year risk of stroke and death was 9.7 %. Extracranial–intracranial bypass is an effective treatment of haemodynamic impairment in patients with internal carotid occlusion. Maintaining low-level morbidity and mortality is possible with a dedicated neurovascular team. This is the only way in which we can reduce the risk of stroke and death in patients with bypass compared to patients treated medically.     

Is clopidogrel beneficial following coronary bypass surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether clopidogrel is superior to aspirin in preventing adverse events post coronary arterial bypass grafting. Altogether 220 papers were found using the reported search, of which four presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. We conclude that if aspirin is not tolerated, clopidogrel is an acceptable alternative, but there is no strong evidence that clopidogrel is superior to aspirin postcoronary surgery.     

Does coronary artery bypass surgery improve survival?

Abstract Objectives. According to guide-lines, coronary bypass surgery improves survival in high risk patients. The evidence for this is more than 20 years old and may be questioned. Long waiting lists for coronary bypass surgery are detrimental but offer the possibility to compare the risk of death before and after surgery. We hypothesized that the risk of death is lower after bypass surgery than before the operation in high risk patients in a more recent cohort. Design and results. Death hazard functions were calculated by the use of Poisson regression scheduled for bypass surgery between 1 Jan 1995 and 31 July 2005. The analyses were performed in two states: 1) in the period after triage until admission for surgery during which optimal medication was intended and 2) after surgery and up to 11 years (corresponding to 57,548 patient years). The probability of death was calculated by entering individual risk profile data into the two multivariable functions. There were several significant differences between the hazard functions in the two states. All variables reflecting angiographic severity of coronary lesions indicated lower risk of death after bypass surgery. The risk associated with left ventricular impairment was lower after surgery (beta coefficients - 0.0546 vs. - 0.0234, p <0.001). Only one variable, age, indicated higher risk after surgery (which is also seen in a general population over time). The reduction of risk was dependent on preoperative risk with a large reduction when preoperative risk was high and vice versa. When preoperative risk was low, however, the risk increased due to surgical mortality. Conclusions. The risk of death is lower after bypass surgery than before the operation in high risk patients. This is most likely explained by a prognostic gain from bypass surgery. The gain is largest in high-risk patients but small or absent in low risk patients.     

Cardiopulmonary bypass: Evidence or experience based?

OBJECTIVE: Evidence-based medicine is emerging as a new paradigm for medical practice. The purpose of this study was to evaluate the amount and quality of scientific evidence supporting principles that are currently applied for cardiopulmonary bypass performance. METHODS: A survey of all German departments of cardiac surgery regarding cardiopulmonary bypass performance disclosed major differences. Consequently, for 48 major principles of cardiopulmonary bypass performance, relevant Medical Subject Headings were identified, and a literature search of the Medline database was performed. Two sequentially applied sets of inclusion-exclusion criteria were selected to assess the best available evidence. RESULTS: Thirty-three thousand articles relating to the subject were identified. Among these, 1500 fulfilled the first set of inclusion criteria: meta-analysis of (randomized) controlled clinical trials and in vitro and animal studies. Rigorous methodological criteria were then applied to further select remaining publications. Ultimately, 225 articles referring to major cardiopulmonary bypass principles were identified as providing the best available evidence. These were graded according to their methodological rigor (susceptibility to bias). The scientific evidence on the investigated cardiopulmonary bypass principles did not prove to be of a high enough level to allow general recommendations to be made. CONCLUSIONS: The scientific data concerning the effectiveness and safety of key principles of cardiopulmonary bypass are insufficient in both amount and quality of scientific evidence to serve as a basis for practical, evidence-based guidelines.     

Capillary leak syndrome after cardiopulmonary bypass in elective, uncomplicated coronary artery bypass grafting operations: does it exist?

OBJECTIVE: Operations coupled with cardiopulmonary bypass may provoke a systemic inflammatory response, and it has been suggested that this responses causes capillary leakage of proteins, edema formation, and even organ failure. However, capillary leak syndrome is mainly a clinical diagnosis and has not been verified as yet by actual demonstration of protein leakage from the circulation. We have therefore measured the disappearance of labeled plasma protein before and after cardiopulmonary bypass. METHODS: Sixteen patients scheduled for elective coronary artery bypass grafting were enrolled in a prospective controlled study. The cardiopulmonary bypass circuit was primed with crystalloids only. Tumor necrosis factor alpha, interleukin 6, interleukin 8, anaphylatoxin C3a, and terminal complement complex C5b9 levels were determined before, during, and 3 hours after cardiopulmonary bypass. The transvascular escape rate of plasma protein from the intravascular compartment was assessed by measuring the disappearance of intravenously injected Evans blue dye before and during the third hour after cardiopulmonary bypass. RESULTS: A significant inflammatory response could be demonstrated by means of the 5 measured mediators after bypass. The maximal increase, as compared with the baseline value, was found for interleukin 6 (36-fold). The transvascular escape rate of Evans blue dye was similar before and after bypass (7.6 +/- 0.6%/h vs 7.3 +/- 0.6%/h). CONCLUSIONS: The above data confirm the systemic inflammatory response induced by cardiopulmonary bypass. Contrary to expectations, the transvascular escape rate of Evans blue dye did not change when comparing values before and after bypass. The data do not support the concept of increased protein leakage in the exchange vessels after bypass. We were unable to demonstrate a capillary leak syndrome.     

Does a hyperoncotic cardiopulmonary bypass prime affect extravascular lung water and cardiopulmonary function in patients undergoing coronary artery bypass surgery?

OBJECTIVE: Different types of colloidal priming for cardiopulmonary bypass (CPB) have been used to reduce fluid load and to avoid the fall of plasma colloid osmotic pressure (COP) that leads to edema formation and consequently can cause organ dysfunction. The discussion about the optimal priming composition, however, is still controversial. We investigated the effect of a hyperoncotic CPB-prime with hydroxyethyl starch (HES) 10% (200;0.5) on extravascular lung water (EVLW) and post-pump cardiac and pulmonary functions. METHODS: In 20 randomized patients undergoing elective coronary artery bypass graft surgery (CABG), a colloid prime (COP: 48 mmHg, HES-group, n = 10) and a crystalloid prime (Ringer's lactate, crystalloid group, n = 10) of equal volume were compared with respect to the effects on cardiopulmonary function. Cardiac index (CI), mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), pulmonary vascular resistance index (PVRI), alveolo-arterial oxygen difference (AaDO(2)), pulmonary shunt fraction (Q(s)/Q(T)), EVLW (double-indicator dilution technique with ice-cold indocyanine green), COP, fluid balance and body weight were evaluated peri-operatively. RESULTS: Pre-operative demographic and clinical data, CPB-time, cross-clamp time and the number of anastomoses were comparable for both groups. During CPB, COP was reduced by 20% in the HES-group (18.9 +/- 3.7 vs. 23.7 +/- 2.2 mmHg, P < 0.05) while it was reduced by more than 50% of the pre-CPB value (9.8 +/- 2.0 vs. 21.4 +/- 2.1 mmHg, P < 0.05) in the crystalloid group (P < 0.05 HES- vs. crystalloid group). Post-CPB EVLW was unchanged in the HES-group but it was elevated by 22% in the crystalloid group (P < 0.05 HES- vs. crystalloid group), CI was higher in the HES-group (3.4 +/- 0.3 vs. 2.7 +/- 0.5l/min, P < 0.05). Fluid balance was less in the HES-group (813 +/- 619 vs. 2143 +/- 538, P < 0.05). Post-operative weight gain could be prevented in the HES-group but not in the crystalloid group (1.5 +/- 1.2 vs. -0.3 +/- 1.5, P < 0.05). No significant differences were seen for MAP, PAP, PCWP, SVRI, PVRI, AaDO(2) and (Q(s)/Q(T)) between the two groups at any time. CONCLUSIONS: Hyperoncotic CPB-prime using HES 10% improves CI and prevents EVLW accumulation in the early post-pump period, while pulmonary function is unchanged. This effect can be of benefit especially in patients with congestive heart failure.     

Extra-anatomical bypass grafting �C a single surgeon's experience

INTRODUCTION

Extra-anatomical bypass grafting is a recognised method of lower limb re-vascularisation in high-risk patients who cannot tolerate aortic cross clamping, or in those with a hostile abdomen. We present a single surgeon series of such procedures and determine relevant outcomes.

PATIENTS AND METHODS

A retrospective review was performed on a prospectively maintained database of patients undergoing femoro-femoral or axillo-femoral bypass surgery between 1986 and 2004.

RESULTS

Patency rates for femoral (n = 28; 32%) versus axillary (n = 59; 68%) bypass procedures at 1 month, 1, 3 and 5 years were (92% vs 93%), (69% vs 85%), (60% vs 72%) and (55% vs 67%), respectively. Patient survival rates for the corresponding procedures and time intervals were (96% vs 90%), (96% vs 67%), (85% vs 45%) and (73% vs 38%) and revealed a significantly lower survival rate in those undergoing axillary procedures (P = 0.002). Limb salvage rates were calculated at (100% vs 91%), (96% vs 84%), (96% vs 81%) and (92% vs 81%) with no statistically significant difference found between the two groups (P = 0.124). Two-thirds of the patients who required major amputation died within 12 months of surgery.

CONCLUSIONS

Acceptable 30-day morbidity, long-term primary patency and survival rates are obtainable in patients suitable for extra-anatomical bypass surgery despite having significant co-morbidities. We have shown 5-year patency rates in those that survive axillary procedures to be as good as those undergoing femoral procedures. Furthermore, surviving patients who evade amputation within a year have an excellent chance of long-term limb salvage.