Moderate Hypothermic Circulatory Arrest (≥ 28°C) with Selective Antegrade Cerebral Perfusion for Total Arch Replacement with Frozen Elephant Trunk Technique.

OBJECTIVES: The optimal hypothermic level during circulatory arrest in aortic arch surgery remains controversial, particularly in frozen elephant trunk (FET) procedures. We describe herein our experience for total arch replacement with FET technique under moderate systemic hypothermic circulatory arrest (≥ 28°C) during selective antegrade cerebral perfusion. METHODS: Between January 2009 and January 2016, 38 consecutive patients underwent elective total arch replacement for various aortic arch pathologies with FET technique using the E-vita Open hybrid prosthesis (Jotec GmbH, Hechingen, Germany). Selective unilateral or bilateral cerebral perfusion under moderate systemic hypothermic circulatory arrest (28.7°C ± 0.5°C) was used in all patients. Minimally invasive total arch replacement with FET via partial upper sternotomy was performed in 15 patients (39%) and in the remaining 23 patients (61%) via full sternotomy. Mean late follow-up was 3 ± 2 years and was 98% complete. Clinical data were prospectively entered into our institutional database. RESULTS: Cardiopulmonary bypass time accounted for 198 ± 58 minutes and the myocardial ischemic time 109 ± 29 minutes. Selective antegrade cerebral perfusion time was 55 ± 6 minutes. Lower body circulatory arrest time was 39 ± 11 minutes. Unilateral cerebral perfusion was performed in 31 patients (82%), and bilateral in 7 patients (18%). Intensive care unit stay was 4 ± 3 days. Thirty-day mortality was 5% (n = 2). Late survival at 3 years was 87 ± 3%. Two patients (5%) required reexploration for bleeding. Patients were discharged after a hospital length of stay of 7 ± 2 days. Postoperative permanent neurologic complication occurred in two patients (5%). Three patients (8%) experienced a transient neurologic disorder. New transient renal replacement therapy was necessary in three patients (8%). No spinal cord injury was noted. CONCLUSIONS: Our data suggest that moderate systemic hypothermic circulatory arrest (≥ 28°C) in combination with antegrade cerebral perfusion can safely be applied for total aortic arch replacement with FET and offers sufficient neurologic and visceral organ protection.

First in Man: Off-Pump Transapical Transcatheter Aortic Valve Implantation and Mitral Valve Repair.

We report the case of an 89-year-old man with severe aortic valve stenosis and concomitant severe mitral valve regurgitation. Due to his age and comorbidities, the patient was not accepted for open heart surgery. After interdisciplinary discussion with the heart team, the patient underwent a minimally invasive off-pump procedure combining aortic valve replacement with mitral valve repair. Cardiac surgeons performed a transapical aortic valve replacement, followed by mitral valve repair applying the NeoChord device (NeoChord Inc, St. Louis Park, MN) under three-dimensional transesophageal echocardiographic guidance by an interventional cardiologist. The patient's further clinical course was uneventful, and he did well on follow-up examinations.

Is More than One Hour of Selective Antegrade Cerebral Perfusion in Moderate-to-Mild Systemic Hypothermic Circulatory Arrest for Surgery of Acute Type A Aortic Dissection Safe?

OBJECTIVES: Surgery for acute type A aortic dissection (AAD) remains a surgical challenge with considerable risk of morbidity and mortality. Antegrade cerebral perfusion (ACP) has been popularized, offering a more physiologic method of brain perfusion during complex aortic arch repair, often necessary in setting of AAD. The safe limits of this approach under moderate-to-mild systemic hypothermic circulatory arrest (≥ 28°C) are yet to be defined. Thus, the current study investigates our clinical results after surgical treatment for AAD in patients with a selective ACP and systemic circulatory arrest time of ≥ 60 minutes in moderate-to-mild hypothermia (≥ 28°C). METHODS: Between January 2000 and April 2016, 63 consecutive patients underwent surgical treatment for AAD employing selective ACP during moderate-to-mild systemic hypothermia (≥ 28°C) with prolonged ACP and circulatory arrest times. Patients' mean age was 59 ± 15 years, and 39 patients (62%) were men. Hemiarch replacement and total arch replacement were performed in 13 (21%) and 50 (79%) patients, respectively. Frozen elephant trunk, arch light, and elephant trunk technique were performed in nine (14%), six (10%), and three patients (5%), respectively. Clinical data were prospectively entered into our institutional database. Mean late follow-up was 6 ± 4 years and was 98% complete. RESULTS: Cardiopulmonary bypass time accounted for 245 ± 81 minutes and the myocardial ischemic time accounted for 140 ± 43 minutes. Mean duration of ACP was 74 ± 12 minutes. The mean lowest core temperature accounted for 28.9 ± 0.8°C. Unilateral ACP was performed in 44 patients (70%); bilateral ACP was used in the remaining 19 patients (30%). Intensive care unit stay reached 6 ± 5 days. New onset of acute renal failure requiring hemofiltration was observed in 8% of patients (n = 5). New postoperative permanent neurologic deficits were found in five patients (8%) and transient neurologic deficits in six patients (10%). There was one case of paraplegia. Thirty-day mortality and in-hospital mortality were 8 (n = 5) and 11% (n = 7), respectively. Overall survival at 5 years was 76 ± 9%. CONCLUSION: Our preliminary data suggest that selective ACP during moderate-to-mild systemic hypothermic circulatory arrest (≥ 28°C) can safely be applied for more than 1 hour even in the setting of AAD.

The relationships between cortisol levels, insulin levels, and thyroid hormones with 24-h urinary sodium excretion in never treated essential hypertensive patients.

BACKGROUND: To study the relationship between cortisol, insulin, and thyroid hormone levels with 24-h urinary sodium (Na) excretion levels in essential hypertensive patients. METHODS: All patients underwent history taking, physical examination, blood pressure (BP) measurement, 12 lead electocardiographic evaluation, routine urine analysis, biochemical analysis including measurement of cortisol, insulin, and thyroid hormone levels, 24-h urine collection to measure urinary Na and protein excretion and creatinine clearance. RESULTS: In total, 68 newly diagnosed hypertensive patients were included. Spearman correlation analysis revealed that 24-h urinary Na excretion was correlated with insulin levels (ρ = -0.473, P < 0.0001), serum cortisol levels (ρ = -0.404, P = 0.0010) and creatinine clearance (ρ = 0.407, P = 0.0010). Linear regression of independent factors has revealed that systolic BP (B = 0.004, CI = 0.001-0.008, P = 0.0170), body mass index (B = 0.014, CI = 0.005-0.023, P = 0.0030), being male (B = 0.077, CI = 0.001-0.153, P = 0.0480), creatinine clearance (B = 0.003, CI = 0.001-0.006, P = 0.0120) and insulin levels (B = -0.008, CI = -0.014 to -0.002, P = 0.0070) were independently related with logarithmically converted 24-h Na excretion. CONCLUSION: In conclusion, we found that insulin but not cortisol and thyroid hormone levels were independently related with 24-h urinary Na excretion in newly diagnosed essential hypertensive patients.

Two cases of valve surgery through right anterior minithoracotomy in presence of severe postmastectomy irradiation sternal damage.

High dose postmastectomy radiation therapy for breast cancer can lead to severe postirradiation sternal damage. Under these circumstances, median sternotomy may be associated with a prohibitive risk of postoperative deep sternal wound infection and alternative approaches have to be evaluated. We report herein the use of a right anterior minithoracotomy through the third intercostal space for isolated aortic valve replacement in one and combined aortic and mitral valve replacement in combination with mitral ring decalcification and coronary artery bypass grafting to the proximal right coronary artery in another patient.

Mitral valve surgery in 6 patients after failed MitraClip therapy.

The MitraClip percutaneous mitral valve repair system, developed as an option for percutaneous mitral repair, was clinically introduced in 2007. From 2010 through 2012, 6 of our patients underwent mitral valve surgery after MitraClip failure. Their mean age was 75 ± 7.7 years (range, 62-87 yr). Three had undergone cardiac surgery previously. In 5 of the 6 patients, mitral regurgitation recurred after initially successful MitraClip deployment and was the indication for surgery. The mean interval between MitraClip implantation and surgery was 106 ± 86 days (range, 0-238 d). Mitral valve repair was feasible in 3 patients; the others underwent valve replacement. All the patients underwent additional cardiac procedures, because the MitraClip worsened existing conditions. Echocardiograms revealed sufficient valvular repairs. Two patients died during hospitalization, one of cerebral infarction and the other of bowel ischemia. Mitral valve repair after failed MitraClip therapy can be complex and a surgical challenge. Careful consideration should be given to appropriate patient selection for MitraClip therapy, because the MitraClip can cause existing pathologic valvular conditions to deteriorate substantially. The interval between MitraClip failure and corrective surgery should be as short as possible. The primary indication is an issue of ongoing discussion.

The relationship between serum total testosterone and 24-hour urinary sodium excretion in never-treated stage 1 essential hypertensive patients.

OBJECTIVES: To study the relationship between serum total testosterone (TT) and 24-hour urinary sodium excretion in newly diagnosed stage 1 essential hypertensive patients with normal renal function. STUDY DESIGN: In total, 80 never-treated stage 1 hypertensive patients were included. All patients provided medical history and underwent physical examination, blood pressure measurement, 12-lead electrocardiography, routine urine analysis, biochemical analysis, 24-hour urine collection to measure urinary sodium and protein excretion, and creatinine clearance calculation. RESULTS: Pearson correlation analysis revealed that logarithmically converted 24-hour urinary sodium excretion was correlated with age (r=-0.399, p<0.0001), body mass index, (r=0.304, p=0.006), systolic blood pressure (r=0.394, p<0.0001), serum potassium (r=0.233, p=0.037), creatinine clearance (r=0.600, p<0.0001), and logarithmically converted serum TT (r=-0.272, p=0.015). Stepwise linear regression analysis revealed that age (p<0.0001), creatinine clearance (p=0.015), systolic blood pressure (p<0.0001), potassium (p=0.021), and serum TT (p=0.002) were independently related to logarithmically converted 24-hour sodium excretion. CONCLUSION: We demonstrated that serum TT levels were independently related to 24-hour urinary sodium amount.

Classical transient receptor potential channel 6 (TRPC6) is essential for hypoxic pulmonary vasoconstriction and alveolar gas exchange.

Regional alveolar hypoxia causes local vasoconstriction in the lung, shifting blood flow from hypoxic to normoxic areas, thereby maintaining gas exchange. This mechanism is known as hypoxic pulmonary vasoconstriction (HPV). Disturbances in HPV can cause life-threatening hypoxemia whereas chronic hypoxia triggers lung vascular remodeling and pulmonary hypertension. The signaling cascade of this vitally important mechanism is still unresolved. Using transient receptor potential channel 6 (TRPC6)-deficient mice, we show that this channel is a key regulator of acute HPV as this regulatory mechanism was absent in TRPC6(-/-) mice whereas the pulmonary vasoconstrictor response to the thromboxane mimetic U46619 was unchanged. Accordingly, induction of regional hypoventilation resulted in severe arterial hypoxemia in TRPC6(-/-) but not in WT mice. This effect was mirrored by a lack of hypoxia-induced cation influx and currents in smooth-muscle cells from precapillary pulmonary arteries (PASMC) of TRPC6(-/-) mice. In both WT and TRPC6(-/-) PASMC hypoxia caused diacylglycerol (DAG) accumulation. DAG seems to exert its action via TRPC6, as DAG kinase inhibition provoked a cation influx only in WT but not in TRPC6(-/-) PASMC. Notably, chronic hypoxia-induced pulmonary hypertension was independent of TRPC6 activity. We conclude that TRPC6 plays a unique and indispensable role in acute hypoxic pulmonary vasoconstriction. Manipulation of TRPC6 function may thus offer a therapeutic strategy for the control of pulmonary hemodynamics and gas exchange.

Impact of mitochondria and NADPH oxidases on acute and sustained hypoxic pulmonary vasoconstriction.

Hypoxic pulmonary vasoconstriction (HPV) matches lung perfusion with ventilation to optimize pulmonary gas exchange. However, it remains unclear whether acute HPV (occurring within seconds) and the vasoconstrictor response to sustained alveolar hypoxia (developing over several hours) are triggered by identical mechanisms. We investigated the effect of mitochondrial and NADPH oxidase inhibitors on both phases of HPV in intact rabbit lungs. These studies revealed that the sustained HPV is largely dependent on mitochondrial complex I and totally dependent on complex IV, whereas NADPH oxidase dependence was only observed for acute HPV. These findings were reinforced by an alternative approach employing lungs from mice deficient in the NADPH oxidase subunit p 47(phox). In these mice (which lack a subunit suggested to be important for the function of most NADPH oxidase isoforms), but not in gp 91(phox)-deficient mice (which represent only one isoform of NADPH oxidases), acute HPV was significantly reduced, while non-hypoxia-induced vasoconstrictions elicited by the thromboxane mimetic U46619 were not affected. We concluded that the acute phase and the sustained phase of HPV are differentially regulated, with NADPH oxidase activity predominating in the acute phase, while a strong dependence on mitochondrial participation was observed for the second phase.