The relationship between diabetes and surgical site infection following coronary artery bypass graft surgery in current-era models of care.

BACKGROUND: Although diabetes is a recognized risk factor for postoperative infections, the seminal Portland Diabetic Project studies in cardiac surgery demonstrated intravenous insulin infusions following open-cardiac surgery achieved near normal glycaemia and decreased deep sternal wound infection to similar rates to those without diabetes. AIM: We sought to examine a contemporary cohort of patients undergoing coronary artery bypass graft surgery (CABGS) to evaluate the relationship between diabetes, hyperglycaemia and risk of surgical site infection (SSI) in current-era models of care. METHODS: Consecutive patients who underwent CABGS between 2016 and 2018 were identified through a state-wide data repository for healthcare-associated infections. Clinical characteristics and records of postoperative SSIs were obtained from individual chart review. Type 2 diabetes (T2D), perioperative glycaemia and other clinical characteristics were analysed in relation to the development of SSI. FINDINGS: Of the 953 patients evaluated, 11% developed SSIs a median eight days post CABGS, with few cases of deep SSIs (<1%). T2D was evident in 41% and more prevalent in those who developed SSIs (51%). On multivariate analysis T2D was not significantly associated with development of SSI (odds ratio (OR) 1.35; P=0.174) but body mass index (BMI) remained a significant risk factor (OR 1.07, P<0.001). In patients with T2D, perioperative glycaemia was not significantly associated with SSI. CONCLUSION: In a specialist cardiac surgery centre using perioperative intravenous insulin infusions and antibiotic prophylaxis, deep SSIs were uncommon; however, approximately one in 10 patients developed superficial SSIs. T2D was not independently associated with SSI yet BMI was independently associated with SSI post CABGS.

Obesity prevalence and associated outcomes in cardiothoracic patients: a single-centre experience.

The objective of this study was to investigate the prevalence of obesity and its relationship with adverse outcomes in ICU cardiothoracic patients. We performed a retrospective analysis of cardiothoracic patients admitted to The Royal Melbourne Hospital ICU between 2002 and 2014. Eight thousand and sixty-four patients who underwent coronary artery bypass, valve replacement/repair, or both, were divided into six categories of body mass index using World Health Organization criteria. Prevalence of obesity over time in the ICU was measured and compared to prevalence of obesity in the adult Australian population. The association between obesity and adverse postoperative outcomes was then analysed. Obesity is currently 1.2 times more prevalent in the Royal Melbourne Hospital ICU cardiothoracic patients than in the adult Australian population, with 33.5% of patients having a body mass index =30 kg/m(2). Over time, this was relatively constant, but an increasing proportion were morbidly obese. Obesity, but not morbid obesity, was associated with reduced 30-day mortality (odds ratio [OR] 0.41). Both obese and morbidly obese patients had reduced odds of return to theatre for bleeding (OR 0.49 and OR 0.19, respectively), but increased odds of new-onset renal failure (OR 1.62 and OR 3.17, respectively). Morbidly obese patients had double the odds of an ICU stay longer than 14 days (OR 2.05). In summary, a growing proportion of our obese ICU patients are morbidly obese, with a dramatically increased length of ICU stay. This has major implications for resource allocation in the ICU, and may inform modelling of future bed utilisation. Obesity, but not morbid obesity, conferred a mortality benefit.

The radial artery in reoperative coronary bypass surgery:.

BACKGROUND: Failure of saphenous vein grafts (SVG) is a significant cause for coronary reoperation (redo CABG). The radial artery (RA) because of its availability, and versatility is well suited to use (together with internal thoracic arteries (ITA) in redo CABG, especially to replace failed SVG. We evaluated our experience where the RA was a major conduit in redo CABG over the past 5 years. METHODS: From July 1996 to June 2002, 590 consecutive patients underwent redo CABG where one or both RA(s) were used, together with LITA or RITA. The mean age was 67.3 years, 82% were male, and 19% diabetic, 419 (71%) had Class III or IV angina, 135 (23%) had left main stenosis, and 210 (36%) had an LVEF < 0.50. There were a total of 877 RA conduits (303 single, 287 bilateral), 518 new LITA or RITA. A mean of 2.8 new distal anastomoses constructed 92% (2.6 per patient)of the arterial grafts. Follow-up was at 1 month, 3 months, and then yearly. The results were compared with 6466 primary CABG performed in the same time frame, and with a prior cohort of 741 consecutive patients having redo CABG without an RA in which identical operative techniques had otherwise been used. RESULTS: The 30-day mortality was 3.9% (23 patients). Morbidity was low. Perioperative myocardial infarction occurred in 16 (2.7%) patients, stroke in 10 (1.7%), sternal infection in 10 (1.7%), donor site infection in 2 (0.3%), and IABP use in 23 patients (3.9%)-including 10 preoperatively. The results were better when compared to a prior cohort of 741 patients with redo CABG (1991 to 1996) without use of the RA. The results were inferior to that of the contemporary primary CABG. Operative mortality was 3.9% versus 0.9%, p = 0.002, myocardial infarction 2.7% versus 0.8%, p = 0.03. CONCLUSION: The use of the RA (together with ITA) in redo CABG achieved total arterial revascularization in 92% of cases and is associated with excellent results, at least equal to or superior to those achieved previously.

[Coronary artery bypass grafting without cardiopulmonary bypass: MIDCAB and OPCAB].

Minimally invasive direct coronary artery bypass grafting via left anterior small thoracotomy (MIDCAB) and coronary artery bypass grafting without cardiopulmonary bypass (OPCAGB) are accepted technique as less invasive than conventional coronary artery bypass grafting (CABG). We reported our experience with these procedures. From 1996 to December 1999, 176 patients underwent MIDCAB or OPCAB with the internal thoracic artery. The left internal thoracic arteries were used for grafting of the left anterior descending artery (LAD) in 131 patients, LAD and diagonal branches sequentially in 8 patients, using free radial artery conduits for grafting of the right coronary artery (RAC) or left circumflex (LCx) in 7 patients, using radial artery conduits as Y-graft from LAD for grafting of the RAC or LCx in 24 patients, and bilateral internal thoracic artery grafting was performed in 4 patients. One patient (0.6%) died in the hospital. One patient (0.6%) had perioperative myocardial infarction. No patient had cerebrovascular accident and sever wood infection. One-hundred-seventy-four patients (98.8%) had resolution of their angina symptom.

The radial artery in coronary re-operations.

OBJECTIVES: Vein graft (VG) failure often leads to coronary re-operation (re-do coronary artery bypass grafting (CABG)). As the internal thoracic artery (ITA(s)) and VG have often already been used and as the VG has usually failed, the radial artery (RA) is ideally suited for use in re-do CABG. We evaluated our experience where the RA(s) was a key conduit in re-do CABG to determine the safety and efficacy and compared this to re-operations where the RA was not used. METHODS: Three hundred and fifty-two consecutive patients who had re-do CABG using the RA(s) from July 1995 to March 1999 were studied: mean age 67.3 years, 209 (60%) angina Class III or IV, past acute myocardial infarction (AMI) in 201 (57%), left ventricular ejection fraction <50% in 109 (31%). Five hundred and thirty-two RAs were used (bilateral in 180 (51%) patients). Additionally, 232 new left ITAs (66% of patients) and 71 new right ITAs (20% of patients) were placed. A total of 1022 distal anastomoses were performed (mean of 2.9 per patient). Follow-up was at 1 month, 3 months, and yearly. The results were also compared to 730 patients having re-do CABG without an RA (January 1990 to June 1995) using identical operative and myocardial protection techniques. RESULTS: RA spasm was noted intra-operatively in four (1.1%) patients, operative mortality was noted in 14 (3.9%) patients, peri-operative myocardial infarction was noted in ten (2.8%) patients, intra-aortic balloon pump was used in nine (2.6%) patients, stroke was noted in six (1.7%) patients, deep sternal infection was noted in two (0.6%) patients, and re-operation for haemorrhage was performed in seven (2.0%) patients. There was only one (0.3%) forearm infection, and two (0.6%) forearm haematomas required drainage. There was no hand ischaemia. When compared to 730 re-do CABG patients without RA, there were significant differences in arterial grafts used (2.6 vs. 1.2, P=0.01), in deep sternal infection (0.6% vs. 2.6%, P=0.01) and donor site infection (0.3% vs. 2.7%, P=0.005) favouring the RA group. Three-year actuarial survival was 89.2% in the RA group and 88.5% in the non-RA group (P=1.0). CONCLUSIONS: Use of the RA in re-do CABG is safe, effective, allows additional conduit choice, reduces donor site and sternal infections, and may avoid further late VG failure.

The right internal thoracic artery graft--benefits of grafting the left coronary system and native vessels with a high grade stenosis.

OBJECTIVE: The left internal thoracic artery (LITA), when grafted to the left anterior descending artery (LAD), is generally accepted as the conduit of choice for coronary artery bypass grafting (CABG). In contrast, the role and efficacy of the right internal thoracic artery (RITA), despite its long-term use as a coronary artery graft, is relatively less understood. Accordingly, in this study, we sought to assess the utility of the RITA as a coronary conduit by examining the long-term patency of both in situ and free RITA grafts and analyzing the association between intraoperative graft and coronary artery variables. METHODS: Nine hundred and sixty-two patients (LITA 962, RITA 432) who had CABG between 1985 and 1998 and underwent re-angiography for evidence of myocardial ischemia were included in this observational analysis. The diameter of the internal thoracic artery (ITA), the presence of a proximal anastomosis with the aorta, the location of the anastomosis with the coronary artery, and the coronary artery diameter, were recorded at the initial procedure. The follow-up was 67.0+/-39.4 months (mean+/-SD, range 0.1-169.5). The relationship between intraoperative variables and graft patency was assessed using Cox proportional hazard models. RESULTS: Highest RITA failure rates were associated with grafting a native coronary artery with a stenosis of less than 60% compared with 80-100% (RR 3. 8 (95% CI, 1.9-7.2) P=0.0001). Grafts to non-LAD arteries had a higher risk of failure, the highest risk ratio being associated with grafting the right coronary artery (RR 4.0 (95% CI, 0.9-17.4) P=0.06)). Free compared with in situ grafts were also associated with a higher risk of failure with this result bordering on statistical significance (RR 1.9 (95% CI, 1.0-6.0) P=0.06)) CONCLUSION: Preference should be given to grafting arteries with a high grade stenosis or occlusion, to grafting left rather than right coronary arteries, and to using in situ rather than free ITA grafts. Passing the RITA to the left, either anterior to the aorta or through the transverse sinus, did not influence patency.

Postoperative radial artery angiography for coronary artery bypass surgery.

OBJECTIVE: To compare radial artery (RA) patency with internal mammary artery (IMA) patency for coronary artery bypass surgery in our early experience. METHODS: Symptomatic as well as asymptomatic patients with > or =1 RA coronary graft underwent postoperative angiography. Each anastomosis was considered separately. A string sign referred to a diffusely narrowed conduit, which did not fill the grafted coronary artery, as well as all occluded conduits. The raw value of P was adjusted for the testing of multiple hypotheses (P'). The patency data for each conduit was divided into two parts. 'Cut-off' stenosis for a conduit was the lowest dividing coronary stenosis at which a difference in patency rate with P< or =0.05 occurred. RESULTS: One-hundred-and-twenty-nine patients had 137 radial arteries and 157 angiograms. Only the most recent angiogram was analyzed for each patient at 13+/-0.7 months (n=129). Overall patency for arterial conduit 91% (n=404) was not different from venous conduit 91% (n=42) and patency for RA 90% (n=226) was not different from IMA 92% (n=178), (P'=0.999). Cut-off stenosis for RA was 70% and IMA was 40%. Patent arterial conduit had a mean coronary stenosis of 85% and non-patent conduit 64%, (P'<0.001). Right coronary territory patency was 82 vs. 94% for other territories (P'=0.022). No overall differences in patency were noted for patients with sequential anastomoses, symptoms or coronary disease at the anastomosis at the time of surgery. Reversible ischaemia was detected in the distribution of only two of 14 string signs in patients undergoing sestamibi exercise protocol following angiogram. CONCLUSION: There were no differences in patency between radial artery and internal mammary artery at 13 months post-operative. Lower coronary stenosis and right coronary territory predicted lower patency. The clinical importance of a string sign remains to be determined.

Total arterial coronary revascularization and factors influencing in-hospital mortality.

OBJECTIVE: To determine if arterial conduit selection or more efficient arterial revascularization techniques influence in-hospital mortality. METHODS: Data from patients undergoing coronary artery bypass surgery at Royal Melbourne Hospital, Australia, between 1 January 1996 and 30 June 1998 (n = 1681) was collected prospectively. Logistic regression analysis was performed. RESULTS: Independent preoperative predictors of increased in-hospital mortality included renal failure, redo coronary artery surgery and intra-aortic balloon pump use. In-hospital mortality for total arterial revascularization 0.7%, radial artery use 0.9%, pedicled arterial revascularization 0.2%, composite arterial conduit 0.4%, and the exclusive Y graft operation 0.3%. These were all associated with reduced in-hospital mortality. Mortality when vein graft was used was 2.9%. Most patients received total arterial revascularization, which was considered the primary surgical strategy. CONCLUSION: Total arterial revascularization, radial artery use and complex arterial reconstructions were associated with reduced in-hospital mortality. Preoperative renal failure, intra-aortic balloon pump use and redo coronary surgery predicted greater in-hospital mortality.

Radial artery harvest technique, use and functional outcome.

OBJECTIVE: To develop a simple harvest technique for radial artery (RA). To investigate the morbidity and functional outcome of RA harvest. METHODS: The neurovascular fascia surrounding the RA is divided. Only loose areolar tissue surrounds this artery making harvest of RA simple and allowing minimal trauma to the RA and surrounding muscles. Topical and intraluminal vasodilators but no systemic vasodilators are used. RESULTS: RA harvest commenced in December 1994. Between 1996 and 30 June 1998, 2167 RA were harvested and used to construct 3105 coronary anastomoses. A dramatic rise in RA use occurred during 1996. More than 80% of patients undergoing coronary artery bypass surgery (CABG) have RA harvested since this time. Total arterial revascularization rate also rose dramatically and is currently 80% of all CABG. This rate has been assisted by a rapid rise in the use of composite arterial grafting where aortic anastomoses can be avoided and currently represents 40% of all CABG. Hand strength was tested in 328 non-selected patients and was not reduced by RA harvest when hand dominance was taken into account. Objective sensation loss was present in 0.3% for the superficial radial nerve and 2.1% for the lateral cutaneous nerve of forearm. Pulse oximetry observations detected statistically significant but clinically irrelevant differences. Scar hypersensitivity occurred in 20%. Only two patients of all patients undergoing RA harvest reported late hand ischaemia. CONCLUSIONS: Harvest of the RA within the neurovascular plane is simple and associated with low morbidity.

Total arterial coronary revascularization: techniques and results in 3,220 patients.

BACKGROUND: To overcome the problems of late vein graft atherosclerosis, occlusion and need of coronary reoperations, we have adopted a strategy of total arterial coronary revascularization. We evaluated our experience with this strategy to establish its safety and efficacy. METHODS: All 3,220 consecutive patients who had total arterial coronary revascularization from January 1988 to June 1998 were evaluated. Data were collected prospectively. The mean age was 62.2 years. Of the patients, 595 (18.8%) had diabetes; 739 (23%) had a left ventricular ejection fraction of less than 0.50; and 484 (15%) were classified unstable/urgent. The conduits included 3,140 left internal thoracic arteries, 1,224 right internal thoracic arteries, and 2,417 radial arteries, 654 of which were bilateral. A Y or T graft with the left internal thoracic artery was used in 467 patients. Patients were followed up at 1 month, 3 months, and yearly thereafter. Postoperative angiography was performed for symptoms or as part of an ethics committee-approved prospective study. RESULTS: The operative mortality rate was 0.7% (21 patients). Complications included stroke in 26 patients (0.8%), myocardial infarction in 27 (0.8%), sternal infection in 35 (1.1%), and reoperation for hemorrhage in 23 (0.7%). The peak level of the myocardial enzyme of creatine kinase was 16.4+/-14.9 IU/L. Twenty-five patients (0.8%) required intraoperative or postoperative intraaortic balloon pump support. Mortality and stroke rates were higher in patients having reoperation (0.6% versus 1.8%; p = 0.11; and 0.7% versus 2.2%; p = 0.07, respectively). Postoperative angiographic patency was 97% at 5 years for the left internal thoracic artery (620 grafts), 89% at 5 years for the right internal thoracic artery (276 grafts), and 91% at 1 year for the radial artery (65 grafts). CONCLUSIONS: Total arterial coronary revascularization can be performed safely with good patency rates in a large number of patients and may potentially avoid the sequelae of vein graft atherosclerosis.

Storage of radial artery grafts in blood increases vessel reactivity to vasoconstrictors in vitro.

BACKGROUND: Although prone to spasm, the radial artery (RA) is commonly used as a graft in coronary artery bypass surgery (CABG). Successful use of the RA as a graft is dependent on techniques to manage vasospasm during operation. We routinely store the RA in a papaverine blood solution after harvesting, a procedure which might damage the endothelium and predispose the RA to postoperative spasm. The aim of the present study was to evaluate the vasodilator and vasoconstrictor responsiveness in freshly obtained and stored segments of RA. METHODS: Discarded segments of RA were obtained at operation from patients undergoing CABG and mounted as 3-mm rings in organ baths for isometric recording of changes in smooth muscle force production. Responses to cumulative additions of acetylcholine, noradrenaline, serotonin, angiotensin II, and the thromboxane A2 mimetic U46619 were normalized to contractions induced by a high potassium solution. RESULTS: Endothelium-dependent relaxation to acetylcholine was not different between preparations from freshly-obtained and blood-stored RA segments. However, maximum contractions to all vasoconstrictors studied were markedly increased in preparations from stored arteries. The sensitivity (pEC50) of stored arteries to U46619, noradrenaline, and angiotensin were also enhanced when compared to preparations from freshly-obtained segments. CONCLUSIONS: Papaverine blood solutions do not damage the endothelium of the RA. The observed heightened vasoconstrictor reactivity of stored arteries, most likely mediated by elements of the blood, indicates that asangineous storage solutions should be explored.

Bilateral radial artery grafts in coronary reconstruction: technique and early results in 261 patients.

BACKGROUND: To achieve arterial myocardial revascularization we have progressively used more single and bilateral internal thoracic artery and radial artery (RA) grafts. We evaluated our early experience with bilateral radial artery to coronary grafts. METHODS: As part of their coronary reconstruction, 261 patients had 522 bilateral RA grafts from March 1995 to June 1997. Mean age was 61.1 years. There were 70 (27%) patients with non-insulin-dependent diabetes and 13 (5%) with insulin-dependent diabetes. Unstable angina was seen in 54 (21%) patients. Left ventricular ejection fraction less than 50% was noted in 74 (28.4%) patients. Coronary revascularization was completed with additional single internal thoracic artery in 229 patients (88%), bilateral internal thoracic artery in 25 patients (9.6%), and vein grafts in 13 patients (5%). Intraluminal 1% papaverine in blood was used. There were 3.6 +/- 0.7 distal anastomoses per patient, with a total of 939, 921 (98%) with arterial conduits and 18 with vein grafts. Five hundred ninety-four (63%) of the anastomoses were with RAs. Of the 522 RA grafts 72 (13.8%) were used sequentially. The RA was most frequently placed to the circumflex marginals (261 patients, 100%) and posterior descending (169 patients, 65%). Proximal RA anastomosis was directly to the aorta in 472 patients, the internal thoracic artery in 42, or another RA in 8. All anastomoses were constructed during a single cross-clamp period (mean, 74.2 +/- 26.6 minutes). RESULTS: Operative mortality was 2 patients (0.8%). Complications included stroke in 2 patients (0.8%), deep internal infection in 2 (0.8%), reoperation for hemorrhage in 1 (0.4%), and myocardial infarction in 2 (0.8%). Mean peak creatine kinase-MB was 13.2 +/- 11.6 IU/L. There were no forearm infections or hand ischemia, but there were 4 (1.6%) hematomas, 1 requiring drainage. Angiography was done on 16 patients with RA grafts, a mean of 4.2 months postoperatively. Twenty of 22 distal anastomoses were patent (91%), and there was 1 occlusion and 1 string sign. CONCLUSIONS: Bilateral RA to coronary grafting extends the scope of arterial myocardial revascularization, and is safe. Late angiographic results are required.

Evolution of complete arterial grafting. For coronary artery disease.

Arterial grafting for the correction of coronary artery disease preceded the use of saphenous vein grafts, but the overwhelming popularity of the saphenous vein from 1970 to 1985 left the development of arterial grafting dormant. Excellent graft patency results from pedicled internal thoracic artery grafting and continued saphenous vein graft failure prompted our unit to explore complete arterial grafting with internal thoracic artery and radial artery grafts. One thousand and fifty-three patients who received a combination of internal thoracic artery and radial artery grafts were compared with 1,156 patients who received internal thoracic artery and saphenous vein grafts. All patients underwent primary coronary artery bypass surgery between 1995 and 1998. The early mortality and morbidity and the probability of survival at 2 years were similar in both groups of patients. Early graft patency studies of 35 radial artery grafts showed 33 (94%) were patent at a mean of 12 months. Complete arterial grafting using internal thoracic and radial arteries is safe and may provide a long-term benefit.

Aortic transection.

BACKGROUND: Traumatic aortic transection is uncommon in those trauma patients reaching hospital alive. METHODS: The Victorian Major Trauma Study (VMTS) received data from 25 hospitals in Victoria, a State of 4.4 million people, and identified 1874 patients with blunt trauma and Injury Severity Score (ISS) greater than 15 over a 2-year period (1 March 1992-28 February 1993 and 1 May 1994-30 April 1995). The Federal Office of Road Safety (FORS) examined coronial data from 1 January 1992 to 31 December 1992. These studies allowed a retrospective, population-based review of experience with aortic transection. RESULTS: The VMTS identified 19 patients who reached hospital, with signs of life at the scene of the accident, during a 2-year period. Of these, 8 left hospital alive: 4 without disability and 4 with disability related to non-thoracic injury. The annual incidence of aortic transection for the State, based on FORS data, was 13 per 1000000, lower than other reported studies. Review of the management of patients in hospital confirmed the usefulness of initial chest X-ray in diagnosis and the high incidence of associated injury. CONCLUSIONS: The study raises a number of issues, including the question of direct referral of patients with severe chest injury to hospitals with cardiothoracic facilities, increased use of transoesophageal echocardiography in diagnosis and increased use of immediate laparotomy and thoracotomy in certain patients.

Results of 1,454 free right internal thoracic artery-to-coronary artery grafts.

BACKGROUND: After beginning our use of bilateral internal thoracic artery grafts in 1985, we found the pedicled right internal thoracic artery grafts limiting, and expanded the application of the right internal thoracic artery by elective use as a free graft. We evaluated the results of patients having a free right internal thoracic artery (FRITA)-to-coronary artery graft as part of their coronary revascularization. METHODS: From 1986 to 1995, 1,454 patients had a FRITA graft. Preoperative characteristics included mean age, 58.8 years (range 29 to 84 years); non-insulin-dependent diabetes, 116 (8%); insulin-dependent diabetes, 7 (0.5%); left ventricular ejection fraction from 0.30 to 0.40, 159 (11%); left ventricular ejection fraction less than 0.30, 14 (1%); and unstable angina, 144 (9.9%). In 11 patients the FRITA was the only graft, in 1,443 a left internal thoracic graft was also used and revascularization completed with additional arterial and vein grafts. There were 3.3 +/- 1.1 distal anastomoses per patient, the aortic clamp time was 49 +/- 12 minutes, and bypass time was 69 +/- 16 minutes. The FRITA was used to reach the circumflex marginal arteries in 718 patients (49.5%), posterior descending artery in 286 (19.7%), diagonal or intermediate in 172 (11.8%), left anterior descending artery in 119 (8.1%), right coronary artery in 115 (7.9%), and left ventricular branch of right coronary artery in 44 (3%). The proximal anastomosis was directly on the aorta in 1,441, other arterial graft in 8, and vein graft in 5. RESULTS: Operative mortality was 13 patients (0.9%); stroke occurred in 14 patients (1%) and myocardial infarction in 19 (1.3%). The peak creatine kinase myocardial isoenzyme serum level was 20.6 +/- 13.6 IU/L. Complications included sternal infection in 18 patients (1.2%) and reoperation for hemorrhage in 23 (1.6%). Survival at 5 and 7 years, respectively, was 96% +/- 2.1% and 94% +/- 2.5%. In 71 patients with a FRITA studied at a mean of 41.5 +/- 14 months postoperatively for recurrent symptoms, 67 FRITA grafts were widely patent (94.5%), 3 displayed a string sign, and 1 was totally occluded. CONCLUSIONS: Use of the right internal thoracic artery as a free graft is safe and effective and allows greater flexibility in arterial coronary revascularization.

Minimally invasive coronary artery bypass surgery without cardiopulmonary bypass.

OBJECTIVE: To report on the initial results of minimally invasive direct coronary artery bypass surgery (MIDCAB) without cardiopulmonary bypass. This is a potential alternative to conventional coronary artery bypass graft surgery, recently introduced to Australia. DESIGN: Prospective survey of patient data. SETTING: Royal Melbourne Hospital campus, Melbourne, Victoria, July 1996 to June 1997. PATIENTS: The first 23 consecutive patients to have a MIDCAB procedure without cardiopulmonary bypass via a small left thoracotomy. The left anterior descending coronary artery was revascularised with the left internal mammary artery. All patients had either recurrent stenosis after previous angioplasty or anatomy unsuitable for angioplasty. OUTCOME MEASURES: Operative morbidity and mortality; graft patency; and patient symptom relief and reoperation rates. RESULTS: Mean age of patients was 57.9 years (range, 29-81), and mean follow-up was 4.0 months (range, 1-10). There was no operative mortality, cardiac infarction or stroke. Mean postoperative stay in the Intensive Care Unit was 30.7 hours and in hospital, 5.3 days. Only one patient needed a blood transfusion (packed red cells). Initial patency of the grafts was confirmed by either angiography (five) or continuous pulse-wave Doppler (23). One patient underwent angioplasty for a stenosis distal to the anastomosis, and two patients (9%) required reoperation for recurrent angina. CONCLUSIONS: MIDCAB can be performed safely, and patient recovery is faster than after conventional coronary artery surgery.

The effect of supplemental oxygen on the incidence of hypoxaemia after premedication in patients undergoing cardiac surgery.

Opiate premedication may cause significant respiratory depression, particularly when other sedative agents such as scopolamine or benzodiazepines are added. This can cause hypoxaemia with potential for worsening myocardial ischaemia in cardiac surgery patients. The aim of this study was to investigate the incidence of hypoxaemia (SpO2 < 90%) in elective patients undergoing cardiac surgery and to assess the efficacy of supplemental oxygen in preventing it. One hundred elective patients without significant respiratory disease or cardiac failure, who received both an opiate and a sedative premedication, were prospectively randomized to receive either oxygen via a facemask at 4 l/min or no oxygen. Continuous arterial oxygen saturation was recorded using a pulse oximeter from the time of premedication until the patient arrived in theatre. An SpO2 < 90% was recorded as a significant event and oxygen was administered to the patients. Six patients were excluded because of equipment failure or protocol violations. The patient groups were comparable with respect to patient demographics, premedication type and dose or the duration of monitoring. In patients receiving oxygen (n = 48) there were no episodes of hypoxaemia (0%). In patients not receiving oxygen (n = 46) there were 14 episodes of hypoxaemia (30%, P < 0.0001). We conclude that there is a significantly high incidence of hypoxaemia in cardiac surgery patients following combined opiate and sedative premedication and that it can be reduced by the routine administration of supplemental oxygen.

Aortic valve replacement in patients 50 years old or younger with the St. Jude Medical valve: 14-year experience.

BACKGROUND AND AIMS OF THE STUDY: Ninety-one of 351 patients who received an aortic valve replacement (AVR) with the St. Jude Medical (SJM) valve at the Royal Melbourne Hospital between 1978 and 1990 were 50-year-old or younger. The results of these patients were retrospectively analyzed so that comparison may be made with the long term results of homograft AVR. MATERIAL AND METHODS: There were 75 males and 16 females. Mean age was 39 years (range 15-50 years). Valve pathologies were, congenital (32), degenerative (30), rheumatic (20), infective endocarditis (7). All patients had warfarin post-operatively. RESULTS: Follow up was complete with a total of 689 patients years, (range 34 months to 14.75 years, mean 7.6 years). There were two operative deaths (2.2%) and three late deaths (0.5 +/- 0.3%/patient-year) and two have undergone subsequent cardiac transplantation. Seventy-eight of 86 survivors (91%) are in NYHA functional Class I. At 10 years, actuarial survival was 94 +/- 2.9%, freedom from embolism was 96.4 +/- 2.4%, and from anticoagulant (AC) hemorrhage 89.4 +/- 6.5%. There were no structural failures; four cases paravalvular leaks were reported. Freedom from non-structural deterioration at 10 years was 95.3 +/- 2.3%. Freedom from reoperation was 95.6 +/- 3.2% at 10 years. Linearized rates (% per patient-year) were for embolism 0.6 +/- 0.5, AC hemorrhage 0.8 +/- 0.2, non-structural dysfunction 0.8 +/- 0.2 for endocarditis 0.4 +/- 0.5, and for reoperation 0.4 +/- 0.4. CONCLUSIONS: The SJM valve prosthesis has performed well in the aortic position in this younger group of patients up to 10 years.