Role of Extra-anatomic Ascending to Descending Bypass in Complex Thoracic Aortic Pathology.

Complex pathology of the distal arch and proximal descending thoracic aorta is usually approached by stent endografting or in situ graft replacement. Oftentimes, these options are not feasible due to unfavorable anatomy, multiple previous procedures, active infection, or presence of concomitant cardiac disease. Thoracic aortic extra-anatomic bypass, as part of an open surgical strategy, is a useful and often the only curative option left for the treatment in these patients. Herein, we describe two cases that illustrate the utility of extra-anatomic thoracic aortic bypass for complex aortic disease.

Clinical outcome after triple-valve operations in the modern era: are elderly patients at increased surgical risk?

BACKGROUND: Despite modern advances in surgical care, triple-valve surgery (TVS) remains a challenge and carries a mortality of 10% to 20%. No validated risk score is available for TVS, and the effect of advanced age is unknown. This study examined our results in the modern era with the aim of identifying perioperative predictors of adverse outcomes. METHODS: Between 1997 and 2013, 131 patients (mean age, 67.2±13.4 years) underwent TVS at our institution. Sixty-eight patients (51.9%) were aged 70 years and older. The most common etiology for aortic and mitral disease was degenerative (77.1%), rheumatic (10%), and endocarditis or prosthetic-related, or both, in the rest. Tricuspid valve disease was functional in 96%. New York Heart Association functional class III/IV was present in 69.4%, and 24% had had previous cardiac operations. One or more concomitant cardiac procedures were performed in 77 patients (58.8%), including coronary revascularization in 54. All aortic procedures were replacements, 14 patients required a prosthetic root conduit and 7 thoracic aorta replacement. Mitral replacements were used in 55%, repairs in 45%, and 96.2% of tricuspid procedures were repairs. Univariate and multivariate analyses were used to determine predictors of adverse outcomes. RESULTS: The 30-day and hospital mortality was 10.6% (n=14). Major complications occurred in 70 (53.4%). Univariate analysis identified New York Heart Association functional class III/IV (p=0.04), preoperative renal failure requiring dialysis (p=0.04), urgent operation (p=0.04), intraaortic balloon pump placement (p=0.02), and postoperative low cardiac output (p<0.0001) as predictors for early death. Proximal aortic operations, urgent operation, and New York Heart Association class IV correlated with increased early mortality (p<0.04) in patients aged 70 and older in addition to their decreased overall survival and decreased likelihood of discharge to home. Overall actuarial survival at 1, 5, and 10 years was 84.5%, 75%, and 45%, respectively. CONCLUSIONS: TVS remains a surgical challenge in the modern era. Despite a trend of increasing age and surgical risk, the early mortality rate and long-term survival remain respectable. Advanced age is associated with increased perioperative risk, but age per se should not be a contraindication for TVS.

Early and midterm outcomes following surgery for acute type A aortic dissection.

OBJECTIVE: Surgical repair of acute Type A aortic dissection (AADA) is still associated with high in-hospital mortality. We evaluated the impact of perioperative risk factors on early and midterm survival. METHODS: Retrospective (2002-2011) database analysis at a single institution of 132 consecutive AADA patients (88 male, age 59.8 ± 13.6). All but five patients underwent repair with open distal anastomoses and hypothermic circulatory arrest: aortic valve replacement/root replacement (n=44, 33.3%) and valve re-suspension/repair (n=88, 66.7%). Ascending aorta, hemi-arch, and total arch repairs were performed in 11, 113, and eight patients, respectively. Antegrade and retrograde cerebral perfusion were used in all but six patients. RESULTS: Overall in-hospital mortality was 17.4% (n=23). Actuarial survival at one, five, and eight years was 82%, 72%, and 62%, respectively. Perfusion time (cardiopulmonary bypass) (226.5 ± 71.3 vs. 177.5 ± 51.7, p=0.0002), aortic cross-clamp time (min) (132.8 ± 45.7 vs. 109.8 ± 41.2, p=0.01), aortic arch (T2) tear (31% vs. 14%, p=0.03), instability (26% vs. 11%, p=0.02), postoperative stroke (38% vs. 14%, p=0.009), and low cardiac output (50% vs. 15%, p=0.04) all correlated with increased perioperative mortality. A Cox proportional hazard model showed perfusion time (hazard ratio [HR]=1.01), postoperative stroke (HR=2.73), age (HR=1.03), and unstability (HR=1.8) as significant risk factors (p<0.05) affecting the overall survival. CONCLUSION: There is a modern trend towards improving overall perioperative outcomes after surgical repair of AADA; however, early mortality and morbidity remain high even in aortic surgery referral centers.

Serpentine left circumflex coronary artery aneurysm as a rare cause of angina with contrast-enhanced multislice computed tomographic evaluation.

Left circumflex coronary artery anomalies are rare causes of cardiac symptoms, especially in the adult population. Herein we describe a case of a 40-year-old man presenting with stable angina who was found to have aneurysmal formation and fistulization of the left circumflex coronary artery to the coronary sinus. Contrast-enhanced multislice computed tomography was very useful in our case for the diagnosis of such anomalies.

Type A aortic dissection complicated with fistulization into the right atrium and right-to-left shunt.

Fistulization between the aorta and the right atrium is a rare complication of ascending aortic dissection. Because of the typical haemodynamic unstability, the diagnosis is often made by bedside or intraoperative transoesophageal echocardiography. The treatment is surgical, but with very high mortality. We describe a case of type A aortic dissection complicated with shock and fistulization into the right atrium with the right-to-left shunt through a patent foramen ovale. Surgical repair was successful.

Hyperhomocysteinemia during aortic aneurysm, a plausible role of epigenetics.

Hyperhomocysteinemia is associated with aortic aneurysm, however, the mechanisms are unclear. We hypothesize that the expression level of genes involved in extracellular matrix (ECM) remodeling, oxidative stress, and enzymes involved in homocysteine metabolism pathway in aortic aneurysm and hyperhomocysteinemia are differentially regulated by DNA methylation. We studied the mRNA levels of MTHFR, SAHH, MMP-1, -9, TIMP-1, -4, peroxiredoxin, NOX-2, -3 (NAPDH oxidase subunits), collagen and elastin in normal and aortic aneurysm tissues from humans and aorta tissue from HHcy (Cystathionine beta synthase heterozygote knockout, CBS+/-) mice treated with high methionine diet. The total RNA was extracted using Trizol method and RT-PCR was performed. Protein expression of MTHFR, H3K9 (trimethyl) and TIMP4 were studied in mice using immunohistochemistry. MTHFR and TIMP4 expression was seen to be increasing in both human aneurysm samples as well as HHcy CBS+/- mice. There was increased expression of MMP9, peroxiredoxin and decreased expression of MMP1, Collagen I and IV was noted in thoracic aortic aneurysm samples. Increased Collagen IV and decreased Collagen I levels were seen in CBS +/- HHcy mice compared to their wild type controls. Since DNA methylation regulates gene expression of enzymes in Hcy metabolism pathway, we also measured the mRNA levels of DNMTs, MBD2 and H3K9. The results suggest an increase in the levels of DNMT1, 3a, MBD2 and H3K9 in CBS +/- aorta compared to their wild type controls. Our findings suggest a possible role of methylation in regulation of expression of genes involved in matrix remodeling and homocysteine metabolism.

Open repair of blunt thoracic aortic injury remains relevant in the endovascular era.

BACKGROUND: Thoracic endovascular aneurysm repair (TEVAR) has been a major advance in the treatment of blunt thoracic aortic injury (BTAI), although many patients still undergo open repair. This study was undertaken to evaluate outcomes with open repair and TEVAR for BTAI. STUDY DESIGN: A retrospective review of all patients with BTAI at a single Level I trauma center from 2001 through 2009 was performed. Patients were grouped according to treatment modality, ie, open repair, TEVAR, or medical management. Direct comparison using standard statistical methods was made between patients undergoing open repair and TEVAR since late 2006 when TEVAR began at our institution using standard statistical methods. Outcomes variables included mortality, paraplegia, length of stay, ICU stay, and ventilator requirements. RESULTS: There were 69 patients in the study, with 36 (52.2%) undergoing open repair, 10 receiving TEVAR (14.5%), 10 patients managed medically (14.5%), and 13 (18.8%) who died during triage. Overall mortality in the pre-TEVAR era was 29.6%. Since the introduction of TEVAR, there have been 8 open repairs. Patients undergoing open repair were significantly younger (32 vs 58 years; p = 0.002) and had smaller aortic diameter (18 mm vs 24.5 mm; p < 0.001) than those undergoing TEVAR. Overall mortality since the introduction of TEVAR has dropped to 12.0% (p = 0.097). CONCLUSIONS: TEVAR and open repair should be viewed as complementary rather than competing modalities for the treatment of BTAI. Having both available allows selection of the most appropriate management technique for each patient, with subsequent improvement in outcomes.

Antegrade versus retrograde cerebral protection in repair of acute ascending aortic dissection.

The objective of this study was to compare retrograde with antegrade cerebral protection during acute aortic dissection repair using cerebral oximetry measurements. Fifty consecutive acute ascending aortic dissection repairs were analyzed. Cerebral oximetry data were collected for 41 of 50. Eight patients who had antegrade cerebral protection alone and 29 of 41 had retrograde cerebral protection alone. The per cent change in cerebral oximetry values during deep hypothermic circulatory arrest from baseline and from prearrest values was compared for the two groups using Student t test. The per cent change from baseline for the antegrade patients was: right 13.8 per cent and left -2.5 per cent; the per cent change from baseline for retrograde patients was: right 0.8 per cent and left 0.2 per cent (P values 0.216 and 0.725, respectively). The per cent change from the prearrest value for the antegrade patients was: right -12 per cent and left -15 per cent; the per cent change from prearrest for retrograde patients was: right -15 per cent and left -16 per cent (P values 0.514 and 0.956, respectively). No compelling evidence for an advantage to either antegrade or retrograde cerebral perfusion was detected. Further study with a focus on neurologic outcomes is warranted.

Inflammatory aneurysms of the ascending aorta: diagnosis and surgical treatment.

Inflammatory aortic aneurysms (IAAs) are rare and located mainly in the infra-renal abdominal aorta. The ascending aorta has been typically spared from this process. We report on two cases of ascending aortic inflammatory aneurysms and describe the available literature on this rare entity.

Proximal thoracic aortic replacement for aneurysmal disease using the freestyle stentless bioprosthesis: a 10-year experience.

BACKGROUND: Porcine bioprosthesis (bioroots) are an attractive surgical strategy for ascending aorta and arch replacement. This study evaluated the perioperative and late outcomes using this strategy for proximal aortic aneurysmal disease. METHODS: Between March 1998 and November 2009, 170 patients (40% women; median age, 70 years) underwent proximal thoracic aortic replacement using the Freestyle (Medtronics Inc, Minneapolis, MN) bioroot, with graft extension in 149 (87.6%). Aneurysmal etiology included degenerative-atherosclerotic (91.2%), acute dissection (5.3%), and chronic dissection (3.5%); 78% had greater than moderate aortic insufficiency. Surgical procedures were bioroot alone or with aortoplasty (12.3%), bioroot with ascending aortic graft (38.2%), bioroot with hemiarch graft (44.1%), and bioroot with total arch (5.3%). Hypothermic circulatory arrest was required in 49%. RESULTS: The 30-day mortality was 4.7% (n=8). The overall complication rate was 58% (n=100), including stroke (6.5%), renal failure (9.2%), respiratory failure (25.9%), and postoperative bleeding (7.6%). Mean hospitalization was 10.5±7.3 days; 38 were discharged to a rehabilitation facility (23.5%). Predictors of 30-day/hospital death were coronary artery disease (p=0.0003), renal insufficiency (p<0.0001), emergent/urgent procedure (p=0.02), and hypothermic circulatory arrest (p=0.002). The 1-year, 5-year, and 10-year survivals were 90%, 80%, and 35% respectively. Freedom from endocarditis and reoperation was 96% at 1 year and 94% and 95% at 5 years, respectively. CONCLUSIONS: Proximal thoracic aortic replacement using a porcine bioroot as part of the repair can be achieved with low perioperative mortality and acceptable late survival in a predominantly elderly population.

Thoracic aortic mobile thrombus: is there a role for early surgical intervention?

BACKGROUND: The diagnosis of thoracic aortic mobile thrombus (TAMT) is rare and is usually made after debilitating embolic events. The optimal treatment strategy is unknown. We report 14 patients with TAMT and aim to better define the role of early (less than 2 weeks) surgical thrombectomy. METHODS: Between February 1996 and February 2010, we treated 14 patients (9 women; aged 32 to 84 years, mean age 51 years) with TAMT. Hypercoagulable disorders or a strong family history of vascular thrombosis, or both, occurred in 9 patients. Diagnosis was made by transesophageal echocardiogram in 6, computed tomography angiography in 7, and digital subtraction angiography in 1. Embolic locations were extremities (n=9), cerebral (n=6), and abdominal (n=6). Aortic thrombi (n=17) locations were ascending/arch (n=7), descending (n=8), and thoracoabdominal (n=2). RESULTS: All patients were initially treated with heparin and aspirin. Thoracic aortic thrombectomies were performed in 8 patients within 2 weeks of diagnosis: left thoracotomy (n=5), thoracoabdominal (n=1), and median sternotomy (n=2). Left atrial-femoral bypass was used in 5 patients, cardiopulmonary bypass in 2, and no support in 1. Additional procedures were celiac artery (n=1) and left subclavian artery (n=2) thrombectomies. Procedures for embolic complications were performed in 7 patients before aortic thrombectomy. Operative mortality was 0%, with no recurrent embolic events after 24±16 months. One patient had thrombectomy of the ascending aorta and medical therapy with warfarin and aspirin for a second concurrent small thrombus in the descending aorta. One patient presented with multiorgan failure and died shortly after admission. Six patients treated medically were discharged on a regimen of oral warfarin and aspirin (14±11 months follow-up), with 2 fatal recurrent embolic events within 6 weeks (p=0.09). CONCLUSIONS: Thoracic aortic mobile thrombus is rare and is commonly associated with morbid thromboembolic events. In our experience, early surgical aortic thrombectomy had a low operative risk and may prevent fatal recurrent embolic events.

Electrical stimulation of cardiomyocytes activates mitochondrial matrix metalloproteinase causing electrical remodeling.

Cardiac arrhythmias, instigated by mechanical and electrical remodeling, are associated with activation of extracellular matrix metalloproteinases (MMPs). However, the connection between intracellular MMPs activation and arrhythmogenesis is not well established. Previously, we determined localization of MMP in the mitochondria using confocal microscopy. We tested the hypothesis that electrical pacing induces the activation of mitochondrial MMP (mtMMP) and is associated with myocyte mechanical dysfunction. Myocytes were isolated and field stimulated at 1 and 4 Hz. Myocyte mechanics and calcium transient was studied using Ion-Optix system. Mitochondrial MMP-9 activation was evaluated using zymography. There was a 25% increase in 1 Hz and 40% increase in 4 Hz stimulation. We observed an increase in mtMMP activation with increase in electrical pacing compared to 0 Hz with a significant increase (p<0.05, n=3). Field stimulation at 4 Hz decreased cell re-lengthening. The levels of calcium transient were reduced with increase in contraction frequency. We conclude that electrical stimulation activates mtMMP-9 that is associated with myocyte mechanical dysfunction.

Tricuspid and aortic valve and ventricular septal defect endocarditis: an unusual presentation of acute Q fever.

Q fever is a rare systemic infection caused by Coxiella Burnetii. The presentation with endocarditis is insidious, with negative blood cultures, and oftentimes it is not obvious in diagnostic imaging studies until hemodynamic changes or valve destruction is reached. We report a case of Q fever endocarditis involving the tricuspid and aortic valves and a congenital ventricular septal defect. Surgical treatment and distinct aspects of this unusual case are herein described.

Repair of mitral valve and left atrioventricular disruption caused by blunt chest trauma.

We describe a case of acute cardiac failure in a patient involved in a motor vehicle accident. A diagnosis of acute mitral regurgitation and left atrioventricular disruption was made with transesophageal echocardiography. Successful repair was performed using the mitral valve leaflets to patch the disruption followed by valve replacement.

Hemiarch aortic replacement for acute type A dissection in a Marfan patient with twin pregnancy.

Type A aortic dissection is a high risk surgical emergency. Its occurrence during pregnancy represents an extremely high risk for death and sequelae for both the mother and the fetus. Surgical treatment in the form of cesarean delivery and aortic repair using hypothermia and circulatory arrest is mandatory in most patients. We report the case of a 29-year-old Marfan female with an acute type A aortic dissection at 34 weeks of a twin pregnancy. She underwent cesarean delivery of male twins followed by repair of the ascending aorta and proximal arch using deep hypothermia and circulatory arrest. The mother and twin babies survived without sequelae and are alive at two years.

Alternative surgical strategy for the treatment of a mycotic aortic arch aneurysm.

We report the case of a 69-year-old man who presented with a symptomatic mycotic aneurysm of the aortic arch. Diagnosis was confirmed by positron emission tomography and by blood cultures positive for Salmonella species. A complete resection of the aortic arch process was performed via left thoracotomy using a cryopreserved aortic homograft and normothermic left heart bypass. The left-sided cerebral vessels were clamped, and adequacy of collateral left brain flow and oxygenation was confirmed by neurophysiologic monitoring. Using this less-invasive operative strategy, we avoided the risks inherent to deep hypothermic circulatory arrest and the use of prosthetic materials.

Adaptive-outward and maladaptive-inward arterial remodeling measured by intravascular ultrasound in hyperhomocysteinemia and diabetes.

BACKGROUND: Coronary artery remodeling implies structural changes in the vessel wall in response to various pathophysiologic conditions. However, the classification of remodeling is unclear. We hypothesized that the adaptive, positive-outward remodeling is a reactive and compensatory response to the stress. The maladaptive negative-inward constrictive remodeling is a passive atherosclerotic condition in which the vessel becomes stiffer. METHODS: Patients with atherosclerotic lesions underwent intravascular ultrasound (IVUS) scans. The size of the vessels distal to and proximal to plaques were analyzed by IVUS. Diabetes was created in mice by an intraperitoneal injection of alloxan (65 mg/kg). To reduce remodeling, mice received ciglitazone, an agonist of peroxisome proliferators activated receptor-gamma (PPARgamma) in drinking water. After 8 weeks, atherosclerotic vessels were analyzed for collagen and elastin. RESULTS: IVUS data suggest an adaptive coronary arterial remodeling was a positive compensatory response to various pathologic stimuli; for example, with the deposition of atherosclerotic plaque, coronary arterial segments enlarged to maintain luminal area. This phenomenon was commonly observed during the initial phases of the development of atherosclerosis. However, negative coronary artery remodeling, or a decrease in vessel area with the formation of atherosclerotic plaque, was maladaptive and was associated with smoking, hypertension, hyperhomocysteinemia, diabetes mellitus, and also after percutaneous coronary interventions (restenosis). In diabetic mice, there was increased collagen and decreased elastin contents; however, treatment with ciglitazone ameliorated the decrease in elastin contents. CONCLUSION: Global enlargement of the coronary vascular tree occurs during pressure and volume overload associated with ventricular hypertrophic states such as athletic conditioning, hypertensive heart disease, and dilated cardiomyopathy. On the other hand, maladaptive coronary arterial remodeling occurs in patients with severe deconditioning, diabetes mellitus, after coronary artery bypass surgery, and in some instances, postintervention.

Seven-year clinical experience with the extracardiac pedicled pericardial Fontan operation.

BACKGROUND: Although improved perioperative outcomes with growth potential of the extracardiac pedicled pericardial Fontan (EPPF) operation have been suggested, no advantage has been demonstrated. METHODS: We retrospectively reviewed our institutional experience of 54 consecutive patients undergoing EPPF between June 1996 and August 2003. Clinical and echocardiographic follow-up was obtained yearly with a mean follow-up of 2.8 +/- 2.0 years. RESULTS: There were 29 males, median age 3.3 years (2-6.8). Median cardiopulmonary bypass time was 79 min (39-295). Fibrillatory arrest was used briefly in 9 patients, of which 6 were for fenestration. One Fontan required takedown (1.8%) and there was 1 death (1.8%) from Candida mediastinitis. Median intensive care unit stay, hospital length of stay, and chest tube drainage were 4 days, 12 days, and 8 days, respectively. Arrhythmias occurred in 7 patients. Three (5.6%) of these had preexisting Holter abnormalities requiring permanent pacemaker implantation. Freedom from thromboembolic events, reoperation, and death at 2.8 years after discharge were 96.2%, 98.1%, and 100%, respectively. All patients were New York Heart Association class I-II, with median oxygen saturation of 94 %. Only 5 patients (9.4%) had mild self-restricted activities. Echocardiographic evaluation revealed excellent ventricular function and flow dynamics. CONCLUSIONS: At midterm follow-up this technique yields outcomes as good as the other Fontan techniques and with further follow-up may prove to be superior. However, at this point no clear advantage has been demonstrated. The low rate of complications and potential for growth are appealing features of this procedure.

Right coronary artery to superior vena cava fistula presenting with 'steal' phenomenon.

A coronary arteriovenous fistula is a rare occurrence. We report a case of a right coronary artery to superior vena cava fistula presenting with myocardial ischemia.