Effects of Acute Pump Speed Changes on Cerebral Hemodynamics in Patients With an Implantable Continuous-Flow Left Ventricular Assist Devices.

Mechanical circulatory support (MCS) with an implantable left ventricular assist device (LVAD) is an established therapeutic option for advanced heart failure. Most of the currently used LVADs generate a continuous stream of blood that decreases arterial pulse pressure. This study investigated whether a change of the pulse pressure during different pump speed settings would affect cerebral autoregulation and thereby affect cerebral blood flow (CBF). The study included 21 haemodynamically stable outpatients with a continuous-flow LVAD (HeartMate II, Abbott, USA) implanted a median of 6 months before the study (interquartile range 3 to 14 months). Arterial blood pressure (measured by finger plethysmography) was recorded simultaneously with CBF (measured by transcranial Doppler ultrasound) during baseline pump speed (8900 rpm [IQR 8800; 9200]) and during minimum and maximum tolerated pump speeds (8000 rpm [IQR 8000; 8200] and 9800 rpm [IQR 9800; 10 000]). An increase in LVAD pump speed by 800 rpm [IQR 800; 1000] from the baseline lead to a significant decrease in arterial pulse pressure and cerebral blood flow pulsatility (relative change ?24% and ?32%, both p < 0.01), but it did not affect mean arterial pressure and mean CBF velocity (relative change 1% and ?1.7%, p = 0.1 and 0.7). In stable patients with a continuous-flow LVAD, changes of pump speed settings within a clinically used range did not impair static cerebral autoregulation and cerebral blood flow.

Modification of human pericardium by chemical crosslinking.

Autologous and allogenic human pericardia used as biomaterials for cardiovascular surgery are traditionally crosslinked with glutaraldehyde. In this work, we have evaluated the resistivity to collagenase digestion and the cytotoxicity of human pericardium crosslinked with various concentrations of glutaraldehyde in comparison with pericardium crosslinked by genipin, nordihydroguaiaretic acid, tannic acid, and in comparison with unmodified pericardium. Crosslinking retained the wavy-like morphology of native pericardium visualized by second harmonic generation microscopy. The collagenase digestion products were analyzed using SDS-PAGE, capillary electrophoresis, and a hydroxyproline assay. Glutaraldehyde and genipin crosslinking protected the native pericardium efficiently against digestion with collagenase III. Only low protection was provided by the other crosslinking agents. The cytotoxicity of crosslinked pericardium was evaluated using xCELLigence by monitoring the viability of porcine valve interstitial cells cultured in eluates from crosslinked pericardium. The highest cell index, reflecting both the number and the shape of the monitored cells was observed in eluates from genipin. Crosslinking pericardium grafts with genipin therefore seems to be a promising alternative procedure to the traditional crosslinking with glutaraldehyde, because it provides similarly high protection against degradation with collagenase, without cytotoxic effects.

Two-stage surgical treatment of inferior vena cava traumatic rupture including urgent transport to a specialized unit.

Inferior vena cava injury as well as major liver injury remains a formidable treatment challenge. The most imminent danger is life-threatening bleeding. In this report, we present a case of polytrauma (Injury Severity Score 35) with arupture of the juxtahepatic inferior vena cava which was successfully treated using two-stage approach. The first part of the treatment consisted of damage control laparotomy at a level I trauma center. After stabilization, the patient was air-transported to receive the definitive treatment at a tertiary care facility experienced in hepatopancreatobiliary and transplantation surgery. As the level of injury was not clear prior to the second stage surgery, a cardiac team also assisted the operation. The second stage procedure was uneventful. The patient is doing well and is preparing to return to work. We believe that experience with major abdominal, thoracic and liver transplantation surgery is beneficial in such cases.

Ventricular assist devices in heart failure: how to support the heart but prevent atrophy?

Ventricular assist devices (VAD) have recently established themselves as an irreplaceable therapeutic modality of terminal heart failure. Because of the worldwide shortage of donors, ventricular assist devices play a key role in modern heart failure therapy. Some clinical data have revealed the possibility of cardiac recovery during VAD application. On the other hand, both clinical and experimental studies indicate the risk of the cardiac atrophy development, especially after prolonged mechanical unloading. Little is known about the specific mechanisms governing the unloading-induced cardiac atrophy and about the exact ultrastructural changes in cardiomyocytes, and even less is known about the ways in which possible therapeutical interventions may affect heart atrophy. One aim of this review was to present important aspects of the development of VAD-related cardiac atrophy in humans and we also review the most significant observations linking clinical data and those derived from studies using experimental models. The focus of this article was to review current methods applied to alleviate cardiac atrophy which follows mechanical unloading of the heart. Out of many pharmacological agents studied, only the selective beta2 agonist clenbuterol has been proved to have a significantly beneficial effect on unloading-induced atrophy. Mechanical means of atrophy alleviation also seem to be effective and promising.

Superficial brachioradial artery (radial artery originating from the axillary artery): a case-report and its embryological background.

A case of anomalous terminal branching of the axillary artery, concerning the variant called superficial brachioradial artery (arteria brachioradialis superficialis) was described, with special regard to its embryological origin. The left upper limb of a male cadaver was dissected in successive steps from the axillary fossa distally to the palmar region. A variant artery, stemming from the end of the third segment of the axillary artery, followed a superficial course distally. It skipped the cubital fossa, ran on the lateral side of the forearm, crossed ventrally to the palm, and terminated in the deep palmar arch. This vessel is a case of so-called "brachioradial artery" (inexactly called a "radial artery with a high origin"). The origin of the brachioradial artery directly from the axillary artery belongs to the rare variants of the arterial pattern of the upper limb. Its incidence is approximately 3%. Moreover, this vascular variant was associated with another one concerning the brachial plexus. The medial cutaneous nerve of the forearm joined the median nerve in the middle third of the arm and ran further distally as a common trunk, as the normal median nerve does. Anatomical knowledge of the axillary region is crucial for radiodiagnostic and surgical procedures, especially in cases of trauma. The superficially located artery brings an elevated risk of bleeding complications in unexpected situations.