Composite graft replacement of the aortic root in acute dissection

Objective: In acute type A dissection the indication for composite graft replacement of the aortic root and the optimal implantation technique are a matter of debate. In this study early and late results of root replacement in acute dissection are determined and compared with supracoronary graft replacement. Two implantation techniques (open vs. inclusion) are evaluated. Methods: Between 1985 and 1995, 207 consecutive patients (mean age 58±12 years, 78% men) were operated for acute type A dissection of the aorta. Root replacement in 50 patients (inclusion technique in 34/50 patients with Cabrol shunt in 15/34 patients, open technique in 16/50 patients) was compared with more conservative procedures in 157 patients: supracoronary graft replacement in 143 patients (with aortic valve replacement in 23 patients) and local repair without graft interposition in 14 patients. Preoperative risk factors, like hemodynamic instability, renal failure, neurologic disorder and coronary artery disease did not differ in the two treatment groups. Results: Early results, survival and reoperation-free survival after 5 years were insignificantly better after root replacement; mortality 10/50 (20%) vs. 38/157 (24%) P=n.s.; hemorrhage 10/50 (20%) vs. 39/157 (25%) P=n.s.; stroke 5/50 (10%) vs. 27/157 (17%) P=n.s.; survival 70±7% vs. 63±4%, reoperation free survival 92±6% vs. 78±5% P=0.0815). For the open technique, early mortality was 18.8 vs. 20.6%, P=n.s. and reoperation free survival at 5 years was 80.7 vs. 65.2%, P=n.s. Perioperative complications did not differ in the two technical groups and a single pseudoaneurysm occurred in the Bentall group. Conclusion: In acute dissection composite graft replacement of the aortic root can be carried out with good early and late results not inferior to more conservative procedures. The open technique is the implantation method of choice and the modified Bentall technique is indicated in situations with increased risk of bleedin

Does retrograde cerebral perfusion via superior vena cava cannulation protect the brain?

Objective: The retrograde cerebral perfusion via cannulation of the superior vena cava is a widespread method for optimising protection of the brain during hypothermic circulatory arrest. Methods: In 14 cadavers (8 females, 6 males) of the local department of pathology, an examination was performed to check the competence of the valves of the internal jugular veins. After a complete preparation of the superior vena cava, the innominate vein and both internal jugular veins, ligating all side branches, a retrograde perfusion on 7 cadavers was installed, documenting flow and pressure of each internal jugular vein (IJV) in vitro. Afterwards, the veins were opened and their valves inspected. Results: In all 14 cadavers, anatomically and functionally competent valves on the right proximal IJV were found. Only 1/14 cadaver had no valve in the left proximal IJV. Additional rudimentary and incompetent valves could be identified in 1/14 cadaver on the distal right IJV, and in 2/14 cadavers on the left IJV. Retrograde flow measurement of 7/14 cadavers revealed 0ml/min in 4/7 cadavers, 6ml/min in 1/7, 340ml/min in 1/7 and 2500ml/min in 1/7 cadaver. Conclusions: As a rule, anatomically and functionally competent valves in the proximal IJV are present. In human beings, they obstruct the direct retrograde inlet to the intracranial venous system, which suggests an unbalanced and unreliable perfusion of the brain. Therefore, retrograde cerebral perfusion by cannulating the superior vena cava may help flushing out embolism and supporting ‘the cold jacket' of the brain. However, its effect of retrograde backflow cannot be a sign of adequate cerebral perfusio

Surgery for acute type a aortic dissection: comparison of techniques

Objective: In order to determine the optimal surgical strategy for acute ascending aortic dissection, the graft inclusion technique was compared with the open resection technique. Methods: Between 1985 and 1995 a consecutive series of 193 patients (77% male, mean age 58 years) had emergency surgery during a mean interval of 13.2 h after onset of symptoms. Graft replacement of the ascending aorta was performed in all patients (supracoronary graft 143/193=74%, aortic root replacement 50/193=26%, aortic valve replacement 73/193=38%, arch replacement 44/193=20%) The open resection technique was applied in 93 patients and the inclusion technique in 100 patients with a Cabrol-shunt in 26%. Preoperative risk factors were equally distributed between groups (inclusion technique vs. open technique): left ventricular ejection fraction≪45% (13 vs. 2%, not significant (n.s.)), neurological deficit (31 vs. 25%; n.s.), systolic blood pressure≪90 mmHg (20 vs. 15%, n.s.) pericardial tamponade (25 vs. 9%, n.s.), renal failure (6 vs. 4%; n.s.). Results: The overall early mortality was 24%. Following graft inclusion it was 31% compared with 16% in the open technique group (P=0.0154). Postoperative complications (graft inclusion vs. open technique): myocardial infarction (9 vs. 12%, n.s.), low cardiac output (40 vs. 32%, n.s.), reexploration for hemorrhage (23 vs. 25%, n.s.). Survival at 8 years was significantly increased in the open technique group (P=0.0300). Pseudoaneurysm formation occurred in 3% of patients and only after graft inclusion. Freedom from reoperation was 80% at 8 years and did not differ between groups. Graft inclusion was an independent significant predictor of early (P=0.0069; relative risk=2.3673) and late mortality (P=0.0119; relative risk=2.0981). Conclusions: Surgery of acute ascending aortic dissection still carries a considerable early mortality whereas the late outcome is satisfactory. The open resection technique is the method of choice showing superior early and late results and avoiding pseudoaneurysm formation. The inclusion technique may be indicated in situations with increased risk of bleeding. A consequent decompression of the perigraft-space could reduce the rate of pseudoaneurysm

Development and Evaluation of a Smartphone-Based Chatbot Coach to Facilitate a Balanced Lifestyle in Individuals With Headaches (BalanceUP App): Randomized Controlled Trial

Background Primary headaches, including migraine and tension-type headaches, are widespread and have a social, physical, mental, and economic impact. Among the key components of treatment are behavior interventions such as lifestyle modification. Scalable conversational agents (CAs) have the potential to deliver behavior interventions at a low threshold. To our knowledge, there is no evidence of behavioral interventions delivered by CAs for the treatment of headaches. Objective This study has 2 aims. The first aim was to develop and test a smartphone-based coaching intervention (BalanceUP) for people experiencing frequent headaches, delivered by a CA and designed to improve mental well-being using various behavior change techniques. The second aim was to evaluate the effectiveness of BalanceUP by comparing the intervention and waitlist control groups and assess the engagement and acceptance of participants using BalanceUP. Methods In an unblinded randomized controlled trial, adults with frequent headaches were recruited on the web and in collaboration with experts and allocated to either a CA intervention (BalanceUP) or a control condition. The effects of the treatment on changes in the primary outcome of the study, that is, mental well-being (as measured by the Patient Health Questionnaire Anxiety and Depression Scale), and secondary outcomes (eg, psychosomatic symptoms, stress, headache-related self-efficacy, intention to change behavior, presenteeism and absenteeism, and pain coping) were analyzed using linear mixed models and Cohen d. Primary and secondary outcomes were self-assessed before and after the intervention, and acceptance was assessed after the intervention. Engagement was measured during the intervention using self-reports and usage data. Results A total of 198 participants (mean age 38.7, SD 12.14 y; n=172, 86.9% women) participated in the study (intervention group: n=110; waitlist control group: n=88). After the intervention, the intention-to-treat analysis revealed evidence for improved well-being (treatment: β estimate=–3.28, 95% CI –5.07 to –1.48) with moderate between-group effects (Cohen d=–0.66, 95% CI –0.99 to –0.33) in favor of the intervention group. We also found evidence of reduced somatic symptoms, perceived stress, and absenteeism and presenteeism, as well as improved headache management self-efficacy, application of behavior change techniques, and pain coping skills, with effects ranging from medium to large (Cohen d=0.43-1.05). Overall, 64.8% (118/182) of the participants used coaching as intended by engaging throughout the coaching and completing the outro. Conclusions BalanceUP was well accepted, and the results suggest that coaching delivered by a CA can be effective in reducing the burden of people who experience headaches by improving their well-being. Trial Registration German Clinical Trials Register DRKS00017422; https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS0001742

Rust for secure IoT applications : why C is getting rusty

Memory corruption is still the most used type of exploit in today’s malware landscape. Human error inevitably introduces memory vulnerabilities into software by using memory-unsafe languages like C and C++, affecting not only security but also safety, dependability, and even basic functionality of devices. The Rust language guarantees memory safety without a garbage collector, promises comparable performance to C/C++, and allows for gradual extension of existing codebases by using its foreign function interface. This report presents the risks of having memory vulnerabilities in embedded applications, what a switch to Rust looks like, how the development experiences differ between Rust and C/C++, and if there are significant differences in performance

Paravalvular leakage after mitral valve replacement: improved long-term survival with aggressive surgery?

Background: Following mitral valve replacement, surgical closure of paravalvular leaks is usually advised in severely symptomatic patients and in those requiring blood transfusions for persisting haemolysis. However, the long-term prognosis of less symptomatic patients or those not needing blood transfusions is unknown. Methods: Between 1987 and 1997, we observed 96 patients with mitral paravalvular leakage. A paraprosthetic leak was diagnosed after a median time of 119 days (range: 1 day-23 years) after primary mitral valve replacement. During an average follow-up of 5 years (range: 1-23 years), 50/96 patients were referred for surgical closure. Results: Compared with patients who received conservative treatment, those referred for surgery had a significantly lower mean preoperative haematocrit (P=0.002) with a higher proportion of patients being in the NYHA class III/IV (P=0.03). Age, gender, left ventricular function and number and size of leaks did not differ between the groups. The 30-day postoperative mortality for valve reoperation was 6% (3/50); during follow-up three further patients died, resulting in an overall mortality rate of 12%. In the group treated conservatively there was a mortality rate of 26% (12/46). Thus, the actuarial survival for patients referred for surgery was 98, 90 and 88% after 1, 5 and 10 years, compared with 90, 75 and 68% for patients treated conservatively (long-rank P=0.03). In addition, there was a significant increase in mean haematocrit levels (P=0.0001) and an improvement in NYHA class III/IV symptoms (P=0.002), vertigo (P=0.001) and fatigue (P=0.001) after surgery. Conclusions: Following mitral valve replacement, a more aggressive surgical treatment is recommended for patients with paraprosthetic leaks. Surgery should be offered to less symptomatic patients, as well as those not requiring blood transfusio

Conservative treatment of the aortic root in acute type a dissection

Objective: In acute type A dissection long-term results of conservative aortic root surgery were compared with the outcome of primary valve and/or root replacement. Methods: Between 1985 and 1995, 199 patients (mean age 59 years, 154 men) were operated on. The aortic root was involved in the dissection process and valve incompetence of varying degree was present without exception. Replacement of a proximal aortic segment was standard procedure in all patients. The aortic valve was preserved in 126 patients: commissural suture resuspension (12 patients), root reconstruction with GRF-glue (gelatine-resorcin-formaldehyde/glutaraldehyde-glue) (114 patients). Valve replacement was performed in 73 patients (50 composite grafts, 23 valve prostheses with separate supracoronary grafts). Preoperative risk factors (valve replacement vs. preservation): coronary artery disease (11 vs. 8%, NS), tamponade (18 vs. 17%, NS), unstable hemodynamics (22 vs. 15%, NS), renal failure (4 vs. 6%, NS), neurologic disorder (19 vs. 32%, NS). Results: The overall early mortality was 23.6% (47/199 patients) and increased after commissural suture resuspension compared with GRF-glue reconstruction (P=NS). Parameters of the early postoperative period did not differ between conservative treatment and root/valve replacement: low cardiac output, 34 versus 38% (P=NS); myocardial infarction, 10 versus 11% (P=NS); hemorrhage, 25 versus 23% (P=NS); duration of intensive care (P=NS). Survival was 61% after 8 years without difference between the two principal treatment groups (P=NS) and between the two conservative subgroups (P=NS). At 2 years, GRF-glue reconstruction had an increased freedom from reoperation on the aortic root (92 vs. 70%, P=0.0253) and event free survival (77 vs. 41%, P=0.0224) compared with suture resuspension. Commissural suture resuspension was an independent, significant predictor for reoperation (P=0.0221, relative risk=4.7130). Conclusion: Surgery for acute type A dissection still carries a considerable early risk. Preservation of the aortic root is safe in the absence of Marfan or annuloaortic ectasia, but a certain incidence of reoperations on the aortic valve and the aortic root has to be accepted. Root reconstruction using GRF-glue is the method of choice and is superior to suture resuspension, with a significantly better reoperation-free and event-free surviva

Explanted cryopreserved allografts: a morphological and immunohistochemical comparison between arterial allografts and allograft heart valves from infants and adults

Objective: Life expectancy of cryopreserved allografts implanted in infants is different from those implanted in adults. A morphological study of explanted allograft heart valves was performed to determine the mechanism of deterioration and to compare cryopreserved arterial and heart valve allografts from adult patients with those explanted from infants. Method: Between 1987 and 1996, 209 cryopreserved allografts were implanted: 125 valved conduits or monocusps to reconstruct the right ventricular outflow tract in congenital heart disease, 50 allograft heart valves to treat native aortic and prosthetic aortic valve endocarditis and 34 cryopreserved arterial allografts to replace mycotic aortic aneurysms or infected aortic prosthetic grafts. Two months to 8 years after implantation, 23 heart valve allografts, 11 right-sided and 12 left-sided, and four arterial allografts had to be explanted for reasons such as degeneration, recurrent infection, aneurysm formation or rupture. Besides conventional staining, immunohistochemical detection of cell populations was performed as follows: CD45RO, CD3 and CD43 for T lymphocytes, CD20 for B lymphocytes, CD68 for macrophages, protein S100 for Langerhans-cells, vimentin for fibroblasts, α-actin for smooth muscle cells and factor VIII for endothelial cells. Results: Explanted cryopreserved allografts were all fibrotic, acellular, non-vital and without endothelial cells. The fibrous tissue was preserved. T lymphocytes, indicating rejection, were found in all right-sided allografts from the paediatric population, but only in 9% of left-sided valves explanted from adults and in one of the four of arterial allografts. Macrophages and Langerhans-cells were found only in right-sided allografts from paediatric patients. Conclusion: Right-sided cryopreserved allografts from a paediatric population showed ongoing cellular rejection. By contrast, there was only a weak T-cell mediated rejection to adult heart valve and arterial allografts. Therefore, similar long-term results can be expected in adult arterial and heart valve allografts, whereas longevity of right-sided heart valve allograft in the paediatric age group seems endangered by cellular rejectio