Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes

AbstractObjectiveDeep sternal wound infection is a dreaded complication of coronary artery bypass surgery, particularly in patients with diabetes. This study determines whether skeletonization of internal thoracic artery conduits compared with pedicled harvesting reduces the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting.MethodsWe reviewed prospectively gathered data on all patients who have undergone coronary artery bypass grafting and received bilateral internal thoracic artery grafts at our institution since 1990. We compared patients with diabetes who received skeletonized (n = 79) versus conventional pedicled (n = 36) internal thoracic artery conduits.ResultsThe proportion of patients taking insulin (19.0% vs 14.0% for skeletonized vs conventional grafts, respectively, P = .6) or oral hypoglycemic agents (68.4% vs 69.4%, P = .9), as well as the prevalence of type I diabetes (2.5% vs 8.3%, P = .18), were similar in both groups. Patients who received skeletonized grafts were more likely to receive a free rather than an in situ right internal thoracic artery graft (93.7% vs 30.6%, P < .001). The prevalence of deep sternal wound infection was significantly lower in patients who received skeletonized grafts compared with patients who received conventional grafts (1.3% vs 11.1%, P = .03). Patients in the skeletonized group were also less likely to develop any (superficial or deep) sternal wound infection postoperatively (5.1% vs 22.2%, P = .03). There was no significant difference in the prevalence of deep sternal wound infection between patients with diabetes who received skeletonized internal thoracic arteries and patients without diabetes who underwent conventional internal thoracic artery grafting (n = 578) (1.2% vs 1.6%, respectively, P = .8).ConclusionsSkeletonization of internal thoracic artery conduits lowers the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. We no longer consider diabetes a contraindication to bilateral internal thoracic artery grafting, provided the internal thoracic arteries are skeletonized

Evolving Surgical Approaches to Bicuspid Aortic Valve Associated Aortopathy

Bicuspid aortic valve (BAV) is the most common congenital cardiac pathology which results from the fusion of two adjacent aortic valve cusps. It is associated with dilatation of the aorta, known as bicuspid valve-associated aortopathy or bicuspid aortopathy. Bicuspid aortopathy is progressive and is linked with adverse clinical events. Hence, frequent monitoring and early intervention with prophylactic surgical resection of the proximal aorta is often recommended. Over the past two decades resection strategies and surgical interventions have mainly been directed by surgeon and institution preferences. These practices have ranged from conservative to aggressive approaches based on aortic size and growth criteria. This strategy, however, may not best reflect the risks of important aortic events. A new set of guidelines was proposed for the treatment of bicuspid aortopathy. Herein, we will highlight the most recent findings pertinent to bicuspid aortopathy and its management in the context of a case presentation

Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications

In cartilaginous fishes, variability in the size of the brain and its major regions is often associated with primary habitat and/or specific behavior patterns, which may allow for predictions on the relative importance of different sensory modalities. The Greenland (Somniosus microcephalus) and Pacific sleeper (S. pacificus) sharks are the only non-lamnid shark species found in the Arctic and are among the longest living vertebrates ever described. Despite a presumed visual impairment caused by the regular presence of parasitic ocular lesions, coupled with the fact that locomotory muscle power is often depressed at cold temperatures, these sharks remain capable of capturing active prey, including pinnipeds. Using magnetic resonance imaging (MRI), brain organization of S. microcephalus and S. pacificus was assessed in the context of up to 117 other cartilaginous fish species, using phylogenetic comparative techniques. Notably, the region of the brain responsible for motor control (cerebellum) is small and lacking foliation, a characteristic not yet described for any other large-bodied (\u3e3 m) shark. Further, the development of the optic tectum is relatively reduced, while olfactory brain regions are among the largest of any shark species described to date, suggestive of an olfactory-mediated rather than a visually-mediated lifestyle

Rheo-PIV of a shear-banding wormlike micellar solution under large amplitude oscillatory shear

We explore the behavior of a wormlike micellar solution under both steady and large amplitude oscillatory shear (LAOS) in a cone–plate geometry through simultaneous bulk rheometry and localized velocimetric measurements. First, particle image velocimetry is used to show that the shear-banded profiles observed in steady shear are in qualitative agreement with previous results for flow in the cone–plate geometry. Then under LAOS, we observe the onset of shear-banded flow in the fluid as it is progressively deformed into the non-linear regime—this onset closely coincides with the appearance of higher harmonics in the periodic stress signal measured by the rheometer. These harmonics are quantified using the higher-order elastic and viscous Chebyshev coefficients e [subscript n] and v [subscript n] , which are shown to grow as the banding behavior becomes more pronounced. The high resolution of the velocimetric imaging system enables spatiotemporal variations in the structure of the banded flow to be observed in great detail. Specifically, we observe that at large strain amplitudes (γ [subscript 0] ≥ 1), the fluid exhibits a three-banded velocity profile with a high shear rate band located in-between two lower shear rate bands adjacent to each wall. This band persists over the full cycle of the oscillation, resulting in no phase lag being observed between the appearance of the band and the driving strain amplitude. In addition to the kinematic measurements of shear banding, the methods used to prevent wall slip and edge irregularities are discussed in detail, and these methods are shown to have a measurable effect on the stability boundaries of the shear-banded flow.Spain. Ministerio de Educación y Ciencia (MEC) (Project FIS2010-21924-C02-02

Cerebral Emboli During Cardiopulmonary Bypass: Effect of Perfusionist Interventions and Aortic Cannulas

Neuropsychological impairment is a very common complication of cardiopulmonary bypass (CPB). The principal cause of postoperative cognitive impairment is thought to be cerebral microemboli during CPB. We recently investigated the effects of perfusionist interventions and aortic cannulation techniques on cerebral emboli production during coronary bypass (CABG) surgery. Patients undergoing isolated CABG were monitored with continuous transcranial Doppler ultrasonography of the middle cerebral artery. Perfusionist interventions were defined as injections of drugs into the CPB circuit or acquisition of blood samples from the CPB circuit. Patients were randomized to receive either standard cannulation of the ascending aorta or cannulation of the distal aortic arch. Cerebral emboli were detected in all patients. The number of emboli per minute was markedly higher during perfusionist interventions than during other time periods. Patients with increased perfusionist interventions had worse neuropsychological outcomes. Cannulation of the distal aortic arch, with placement of the cannula tip beyond the cerebral vessels, resulted in significantly less cerebral emboli than cannulation of the ascending aorta. Perfusionist interventions are a common source of cerebral microemboli during CPB, and may contribute to postoperative neuropsychological impairment. Care should be taken to minimize the introduction of air into the bypass circuit during CPB. Provided it is performed safely, distal aortic arch cannulation is a useful technique for reducing cerebral emboli during cardiac surgery

Replacement of the ascending aorta with reduction of the diameter of the sinotubular junction to treat aortic insufficiency in patients with ascending aortic aneurysm

ObjectiveAscending aortic aneurysm often causes dilation of the sinotubular junction with consequent aortic insufficiency despite normal aortic cusps.MethodsReplacement of the ascending aorta with reduction of the diameter of the sinotubular junction to correct aortic insufficiency was performed in 103 consecutive patients. Twenty-nine also needed repair of cusp prolapse. The patients’ mean age was 65 ± 12 years and all had ascending aortic aneurysm; 63 also had arch aneurysm and 21 had aneurysm of the entire aorta. The aortic insufficiency was graded as moderate in 54 patients and severe in 49. Patients were followed up prospectively and had echocardiographic studies annually. The mean follow-up was 5.7 ± 3.4 years.ResultsThere were 2 operative and 30 late deaths. Cardiovascular events were the cause of death in 19 patients. Arch aneurysm and age were the only predictors of late death. Overall survival at 10 years was 54% ± 7%. Seven patients had moderate and 1 had severe aortic insufficiency. The freedom from moderate or severe aortic insufficiency at 10 years was 80% ± 7% and from severe aortic insufficiency, 98% ± 1%. Two patients required aortic valve replacement, 1 because of severe aortic insufficiency and 1 for endocarditis. The freedom from aortic valve replacement at 10 years was 97% ± 1%. At the latest follow-up, 98% of the patients were in functional class I or II.ConclusionsReduction in the diameter of the sinotubular junction restores aortic valve competence in patients with ascending aortic aneurysm and aortic insufficiency with normal aortic cusps. Late survival of these patients is suboptimal because they often have extensive aneurysmal disease

Late results of heart valve replacement with the Hancock II bioprosthesis

AbstractObjective: To review the late clinical outcomes of patients who had isolated aortic or mitral valve replacement with the Hancock II bioprosthesis. Methods: From 1982 to 1994, 670 patients underwent isolated aortic valve replacement and 310 underwent isolated mitral valve replacement with the Hancock II bioprosthesis (Medtronic Inc, Minneapolis, Minn). Mean age was 65 ± 12 years in both groups. Most patients were in New York Heart Association functional classes III or IV, and concomitant coronary artery disease was present in 44% of patients in the aortic valve group and 41% of patients in the mitral valve group. Patients were followed up prospectively at periodic intervals. Mean follow-up was 87 ± 45 months in the aortic valve group and 83 ± 50 months in the mitral valve group, and it was 99% complete. Results: Actuarial survival at 15 years was 47% ± 3% in the aortic valve group and 30% ± 5% in the mitral valve group. Older age, advanced functional class, impaired left ventricular function, active endocarditis, and coronary artery disease were independent predictors of late death. The freedom from thromboembolic complications at 15 years was 83% ± 3% in the aortic and 87% ± 3% in the mitral valve group. The freedom from infective endocarditis at 15 years was 96% ± 1% in the aortic and 91% ± 1% in the mitral valve group. At 15 years, the actuarial and actual freedom from structural valve deterioration was 81% ± 5% and 90% ± 3%, respectively, in the aortic group and 66% ± 6% and 83% ± 3%, respectively, in the mitral group. Younger age, mitral valve position, and poor ventricular function were independent predictors of structural valve deterioration. The freedom from repeat valve replacement at 15 years was 77% ± 5% in the aortic group and 69% ± 6% in the mitral. The vast majority of patients had functional improvement after valve replacement. Conclusions: The Hancock II bioprosthesis has provided good clinical outcomes and is a durable valve, particularly in the aortic position in older patients. (J Thorac Cardiovasc Surg 2001;121:268-78