Hugh S. Paterson

Lethal Postoperative Coronary Artery Spasm

BACKGROUND Coronary artery spasm in the immediate postoperative period after a coronary operation is recognized infrequently. Its severity is variable and manifestations unpredictable. The diagnosis is usually made by an awareness of the possibility and thereafter by exclusion of other causes of myocardial ischemia. An opportunity for a positive diagnosis is rarely available. METHODS The case reports of 3 patients with similar presentations of ischemic heart disease and with severe manifestations of coronary artery spasm in the postoperative period are presented. RESULTS All 3 patients were women aged 55 to 60 years. All had single-vessel coronary artery disease involving the left anterior descending artery and underwent a left internal mammary artery bypass graft. Severe manifestations of myocardial ischemia of abrupt onset developed approximately 7 hours postoperatively in each patient. One patient died of severe hemodynamic deterioration from which resuscitation was unsuccessful. Another sustained a large anterior myocardial infarction despite graft patency. The third patient was supported by an intraaortic balloon pump and made a full recovery. CONCLUSIONS The early diagnosis of coronary artery spasm is achieved by an awareness of the condition. The institution of early appropriate management may prevent its consequences.

Phrenic nerve injury associated with high free right internal mammary artery harvesting

BACKGROUND The right phrenic nerve is at risk of injury during high mobilization of the right internal mammary artery (RIMA). The incidence and implications of this injury have not been previously defined. METHODS Prospectively collected data on all patients who underwent RIMA harvesting between January 1995 and February 2002 were analyzed. Thirty-one patients with right phrenic nerve injury were identified and the medical charts reviewed. Phrenic nerve injury was diagnosed when a postoperative chest roentgenogram showed the right hemidiaphragm to be two or more intercostal spaces higher than the left, or transection of the nerve was seen intraoperatively. Investigations included fluoroscopy and spirometry in upright and supine positions. Diaphragm plication was offered for symptom control. Subsequent follow-up was undertaken to determine the incidence of spontaneous recovery of diaphragm function and the benefits of diaphragm plication. RESULTS Seven hundred and eighty-three patients underwent high mobilization of the RIMA with proximal detachment for use as a free graft. Thirty-one patients with right hemidiaphragm dysfunction were identified in the postoperative period providing an injury incidence of 4% (confidence interval, 2.6% to 5.3%). Of these, 12 patients underwent diaphragm plication (4 early and 8 late), 14 patients achieved spontaneous recovery, and 5 patients were lost to follow-up. The supine to upright forced vital capacity ratios at the time of phrenic nerve dysfunction, after diaphragm plication, and after spontaneous recovery were 0.79, 0.90, and 0.96 respectively. CONCLUSIONS The incidence of phrenic nerve injury associated with high RIMA harvesting was 4% but spontaneous recovery may be anticipated in two thirds (14 of 22) of patients in whom the injury is identified postoperatively. High RIMA harvesting should be used with caution in patients with preoperative pulmonary dysfunction in whom phrenic nerve injury would be poorly tolerated.

Tunnelling versus open harvest technique in obtaining venous conduits for coronary bypass surgery

BACKGROUND The tunnelling as opposed to the open harvest technique for harvesting long saphenous vein for coronary artery bypass procedures is a less frequently used technique as it requires more handling of the vein and this may induce trauma. This study aims to compare the degree of endothelial denudation and donor site morbidity between the two different harvest techniques. METHODS Saphenous vein segments in 78 patients (45 in tunnelling versus 33 in open harvest group) undergoing coronary artery bypass procedures were examined by light microscopy and graded according to the extent of endothelial denudation varying from grade 1 (most preserved) to grade 6 (>90% endothelial denudation). Clinical parameters relating to donor site morbidity including leg wound pain and infection were also assessed. RESULTS There was no statistical difference in the age, sex, macroscopic vein quality, length and time taken to harvest the veins between the two groups. The tunnelling technique always used thigh saphenous vein whereas nearly a third of veins harvested by the open harvest technique were lower leg veins (P=0.001). The tunnelling technique resulted in an endothelial score of 2.5 compared with 3.3 for the open harvest technique (P < 0.001). In addition, saphenous vein tunnelling resulted in significantly less leg wound pain (1.2 vs. 1.8, P=0.001), no leg wound infection (compared with 12.2% in open harvest group, P=0.02) and produced cosmetically more acceptable scars. Furthermore, length of hospital stay was significantly prolonged to 19.3 days in those with leg wound infection compared to 8.7 days in those without leg wound infection (P < 0.001). CONCLUSIONS These results show that saphenous vein tunnelling is an attractive alternative to the open harvest technique in obtaining venous conduits for coronary artery bypass procedures.

Thoracoscopic evacuation of dead hydatid cyst

Advances in video-assisted thoracoscopic surgery allow investigation and management of a wider range of pleural and pulmonary diseases. After percutaneous cavernostomy, a thoracoscope may be used for removal of foreign material from within an intrapulmonary cavity. A case of a dead hydatid cyst treated by such thoracoscopic evacuation is described. The procedure is simple and effective and is recommended for use when there is a delay in spontaneous resolution. Case report. A 13-year-old black boy came to his local hospital with a productive cough and a fever. Chest radiography revealed a right pulmonary cavity with a fluid level and a left lower lobe spherical opacity. Percutaneous needle aspiration of the lesion on the right side resulted in empyema. The patient was referred for further management. At the referral hospital, it was concluded from radiographic examination that the opacity on the left side was an uncomplicated hydatid cyst 1 and the proven right empyema had resulted from aspiration of a hydatid cyst complicated by infection. Tube thoracostomy effectively drained the right pleural space. By means of the Seldinger technique aided by fluoroscopy, the pulmonary cavity on the right side was intubated and drained of pus. The patients fever subsequently subsided, and his general condition improved. Something resembling the crumpled remains of a dead hydatid cyst within the pulmonary cavity on the right side could be seen on a chest radiograph (Fig. 1). Despite the presence of a bronchocutaneous fistula, as evidenced by the production of purulent sputum and the cavernostomy tube air leak, the residual remnants of this cyst were not evacuated during a 2-week period. The uncomplicated hydatid cyst on the lefl side was removed through a left thoracotomy, followed by capitonage. The right intrapulmonary tube was removed, and the cavity on the right side was entered thoracoscopically through the cavernostomy track. This allowed inspection of the space and easy removal of the dead hydatid cyst, with the cavity being left clean after suction. Open tube cavernostomy drainage was instituted for a further 2 weeks, by which time there was a satisfactory reduction in the size of the cavity. The tube was removed, and after a further short period of clinical and radiologic surveillance, the patient was dis-

Full myocardial revascularization with bilateral internal mammary artery Y grafts.

BACKGROUND Bilateral internal mammary artery (BIMA) grafting in coronary artery surgery provides better long term outcomes than single internal mammary artery and saphenous vein grafting but the optimum configuration of BIMAs has not been established. This study analyzed perioperative and late outcomes of patients who underwent BIMA grafting with a composite Y configuration. METHODS Patients (n=922) who underwent BIMA Y grafting were identified from a cardiac surgical database and then cross matched against hospital and cardiology databases and the state death register to identify episodes of repeat coronary angiography, cardiac surgical re-intervention and death. Analysis of repeat angiography was performed after retrieval of the angiogram reports. RESULTS In 95% of patients, full myocardial revascularization was achieved with BIMAs alone, using a composite Y configuration with an average of 4.1 IMA to coronary artery anastomoses per patient. The perioperative mortality was 1.5% and the 5-, 10- and 15-year survival estimates were 95%, 87% and 77% respectively. Analysis of 166 symptom-driven post-discharge coronary angiograms showed grafts to the left anterior descending artery and increasing severity of coronary artery stenosis at preoperative angiography as predictors of anastomotic patency. CONCLUSIONS Full myocardial revascularization can be achieved with reasonable safety in most patients with triple vessel disease and good left ventricular function, and provides good late survival.

Semi-skeletonized internal mammary artery grafts and sternal wound complications.

This study aimed to evaluate the risk factors for sternal wound complications in patients undergoing myocardial revascularization using bilateral semi-skeletonized internal mammary arteries. Prospectively collected data on 751 patients undergoing coronary artery surgery from September 1994 to August 2002 were analyzed. The mean age of the patients was 56 years, 633 (84%) were male, 44 (6%) were over 66 years of age, and 170 (23%) were diabetic. Forty-four (5.9%) patients developed sternal wound complications. Among these cases, sternal infection occurred in 22 (2.9%) patients, of which 15 (2.0%) had sternal infection with mediastinitis and 7 (0.9%) had sternal infection alone. Independent risk factors for any sternal wound complications were peripheral vascular disease, diet-controlled diabetes, and delayed sternal closure. The risk factors for sternal infection were diabetes, postoperative pulmonary complications, and postoperative stroke. The perioperative mortality rate was 1.5% (11 patients), including 2 patients who had sternal wound complications. The use of bilateral semi-skeletonized internal mammary artery conduits carries a comparable sternal wound complication rate as conduits harvested by other techniques.

Bilateral Internal Thoracic Artery Composite Y Grafts: Analysis of 464 Angiograms in 296 Patients

BACKGROUND The use of bilateral internal thoracic arteries (BITA) in coronary artery bypass graft surgery improves patient survival. The optimum BITA graft configuration is unknown. This study evaluates outcomes after the use of bilateral internal mammary Y grafting as the primary grafting strategy. METHODS Patients who underwent BITA composite Y grafting (n = 1,011) between October 1994 and March 2009 were identified from a cardiac surgical database. Follow-up (mean 12 years) was obtained by cross-reference with the state death registry and local cardiology databases. RESULTS Perioperative mortality was 1.6%. Kaplan-Meier 10-year survival was 87.2%. There were 464 episodes of postdischarge angiography in 296 patients, at an average of 5.5 years to first angiography. Graft failure occurred in 151 patients, predominately affecting the right ITA limb (n = 139). Degree of native vessel stenosis (odds ratio [OR] 0.66 per 10% increase), anatomic territory grafted (circumflex OR 2.64, right coronary OR 6.73 versus anterior), and end-to-side free wall anastomoses (OR 1.98) predicted anastomotic occlusion. The left anterior descending artery graft patency was unaffected by sequential grafting. Progression to graft failure after the first angiogram was rarely seen in the 111 patients who had serial angiography. CONCLUSIONS Outcomes of BITA Y grafting are similar to those for other BITA configurations. The rate of presentation with arterial graft dysfunction decreases over time. Although competitive flow affects anastomotic patency, there is no threshold at which risk of occlusion substantially increases.

Outcomes of cardiac surgery in chronic kidney disease

OBJECTIVE To identify predictors of early and late outcomes of cardiac surgery in patients with chronic kidney disease. METHODS Patients (n=545) with serum creatinine≥200 μmol/L or renal dialysis were identified from databases maintained by the largest Sydney cardiothoracic surgical units with data consistent with the Australian and New Zealand Society of Cardiothoracic Surgeons data definitions. The patient data were matched against the National Dialysis Database and the New South Wales Register of Births, Deaths, and Marriages. Statistical analysis was used to identify predictors of early and late outcomes. RESULTS The Kaplan-Meier estimate of 1-, 5-, and 10-year survival for all patients was 78%, 56%, and 36%, respectively. The outcomes were similar after coronary bypass surgery and valve replacement and were also similar for dialysis and nondialysis patients. The odds ratios for the significant independent predictors of outcomes were, for perioperative death, age (1.4 per decade), emergency surgery (7.0), redo surgery (3.8), left ventricular impairment (moderate, 2.7; severe, 4.4); for new early postoperative dialysis, estimated glomerular filtration rate<20 mL/min (3.8), emergency surgery (2.7), tricuspid valve surgery (4.4); for new permanent dialysis within 6 months of surgery, serum estimated glomerular filtration rate<20 mL/min (odds ratio, 4.6). The hazard ratio for the independent predictors of late death in those alive 6 months after surgery was 1.4 per decade for age and 1.4 for moderate or severe left ventricular impairment. CONCLUSIONS Left ventricular impairment is a risk factor for perioperative and late death in patients with kidney disease. After cardiac surgery, preoperative dialysis-dependent and dialysis-free patients had similar long-term outcomes.

Intermittent Tepid Blood Cardioplegia Improves Clinical Outcome

Intermittent antegrade cold blood cardioplegia is the predominant method of myocardial protection, but recent studies suggest that warm or tepid blood cardioplegia may improve the return of myocardial metabolic and contractile function. Data were collected prospectively on 1,533 patients undergoing cardiopulmonary bypass in a single surgeons practice. The use of intermittent antegrade cold (4°C) blood cardioplegia in 951 consecutive patients from September 1994 to November 1997 was compared with intermittent antegrade tepid (28°C) blood cardioplegia in 582 consecutive patients from July 1998 to July 2000. The two groups were similar, but the symptom class was more severe and there were more redo and combined procedures and more operations within 7 days of myocardial infarction in the tepid group. Significant clinical benefits identified in the tepid group included reduced usage of intraaortic balloon pumping postoperatively (4.4% versus 2.2%) and reduced incidence of postoperative atrial fibrillation (25.7% versus 20.6%). There was no significant difference in mortality, perioperative myocardial infarction, cerebrovascular events, or use of inotropics between the groups. Intermittent tepid blood cardioplegia is clinically appropriate and safe to use in patients undergoing cardiac surgery.

Competitive flow in coronary bypass surgery: The roles of fractional flow reserve and arterial graft configuration

From the Faculty of Medicine, University of Sydney, The Baird Institute of Applied Heart & Lung Surgical Research, Sydney, New South Wales, Australia; and Department of Cardiovascular Surgery, John Radcliffe Hospital, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom. Received for publicationMarch 22, 2017; revisions receivedMay 4, 2017; accepted for publicationMay 29, 2017; available ahead of print June 23, 2017. Address for reprints: Hugh S. Paterson, FRACS, The Baird Institute, 305/100 Carillon Ave, Newtown, New South Wales 2042, Australia (E-mail: patersonh@aol.com). J Thorac Cardiovasc Surg 2017;154:1570-5 0022-5223/