Minimizing visceral organ ischemia time for open repair of thoracoabdominal aortic disease: Description of a new method.

Minimizing ischemic injury during surgical repair of thoracoabdominal aortic aneurysms (TAAAs) is vital for preventing complications such as paraplegia and acute renal failure. In this report, we describe a new technique for TAAA open repair that aims to minimize visceral organ ischemia times. Unlike typical Crawford extent II TAAA open repair, which begins with aortic clamping and proceeds from the proximal to the distal anastomoses, our method reverses the anastomosis order and minimizes aortic clamping. Between January 2016 and December 2020, we used this approach in 29 patients undergoing TAAA repair. We present one of these cases, a 29-year-old patient with progressive aneurysmal dilatation of a DeBakey type III chronic aortic dissection that extended beyond the aortic bifurcation. Our technique reduced aortic cross-clamping, left heart bypass, and internal organ and spinal cord ischemia times and appears to be safe and effective.

Organometallic Synthesis of 2,3,6,7-Tetrasubstituted 1,8-Bis(dimethylamino)naphthalenes for Investigation of the Double Buttressing Effect in Proton Sponges.

The lithiation of 2,7-disubstituted derivatives of 1,8-bis(dimethylamino)naphthalene (DMAN, proton sponge) bearing potentially ortho-directing OMe, NMe2, and SMe groups was studied. It has been shown that OMe groups facilitate selective dual ß-lithiation of the naphthalene moiety while the 2(7)-NMe2 groups allow only monolithiation presumably due to the decreased acidity of the ring C-H bonds and conformational immobilization after coordination to the lithium atom. In contrast, the SMe groups provided no ring lithiation and underwent deprotonation of their methyl fragment. The first representatives of previously unknown 2,3,6,7-tetrasubstituted DMANs have been synthesized in good yield after treatment of 2,7-dimethoxy-3,6-dilithio DMAN with the appropriate electrophiles (MeI, Me2S2, Me3SiCl, DMF, etc.). Because the exceedingly high basicity of 2,7-dimethoxy DMAN is commonly attributed to the so-called "buttressing effect" (BE), the availability of 2,3,6,7-tetrasubstituted species provided the first opportunity to study the double BE version. Using X-ray diffraction and basicity measurements, we showed that due to the high conformational mobility of the methoxy groups, the most striking manifestations of double BE are the strong planarization of peri-NMe2 groups and a significant decrease in basicity, while the length and the other properties of the intramolecular NHN hydrogen bond in the corresponding protonated species undergo minor changes.

Surgical treatment of Kommerell's diverticulum.

Kommerell's diverticulum (KD) is a rare congenital vascular abnormality due to the formation of an abnormal aortic arch, most commonly associated with dilatation at the proximal part of the aberrant subclavian artery. This article describes an option of surgical treatment in a patient with KD. The proposed new technique of aortic arch surgical reconstruction with a stent-graft placement in the descending aorta reduces CPB time, aortic clamp and circulatory arrest time.

Combination of "Buttressing" and "Clothespin" Effects for Reaching the Shortest NHN Hydrogen Bond in Proton Sponge Cations.

A series of previously unknown 2,4,5-tri- and 2,4,5,7-tetrasubstituted 1,8-bis(dimethylamino)naphthalenes and their salts with HBF4 containing bulky spherically shaped substituents (Me, Br, and SiMe3) in the naphthalene ring has been synthesized. Using XRD analysis of 11 samples, the influence of the so-called "buttressing" and "clothespin" effects on their molecular structure and the NHN hydrogen bond geometry in the solid cations were investigated. The combined action of both effects has been shown to significantly increase the compression of the hydrogen bond. As a result, the previous record of the hydrogen bond shortness (N···N = 2.524 Å) has been surpassed in favor of 2.502 Å found for the tetrafluoroborate of 2,4,5,7-tetramethyl-1,8-bis(dimethylamino)naphthalene. The molecular structure of the latter differs by perfect symmetry and practically barrier-free proton transfer in the [NHN]+ bond. On the basis of the results of quantum-chemical calculations, it is suggested that the value of 2.502 Å likely represents or lies very close to the theoretical limit for the short hydrogen bonds between the amine-type nitrogen atoms.

Left ventricular assist device implantation combined with surgical ventricular reconstruction.

Nine months after sustaining a transmural anteroseptal myocardial infarction, a 45-year-old man presented with ischemic heart disease, severe mitral valve insufficiency, New York Heart Association functional class IV congestive heart failure, and a left ventricular aneurysm. Coronary angiography revealed 3-vessel disease. Echocardiography showed severe left ventricular impairment, pronounced thrombosis in the left ventricular apex, and low myocardial reserve. To reduce the high risk of performing left ventricular and mitral valve reconstruction concurrently with revascularization, we decided to perform ventricular reconstruction and to implant a Berlin Heart INCOR left ventricular assist device as a bridge to heart transplantation. The patient had an uncomplicated recovery, was discharged from the hospital with symptomatic improvement after 20 days, and was placed on the list for heart transplantation. We describe the patient's case, the surgical procedure, and the reasoning behind the chosen course of treatment.