Efficacy of biomaterials for lateral bone augmentation performed with guided bone regeneration. A network meta-analysis

Bone regeneration is often required concomitant with implant placement to treat a bone fenestration, a dehiscence, and for contouring. This systematic review assessed the impact of different biomaterials employed for guided bone regeneration (GBR) simultaneous to implant placement on the stability of radiographic peri-implant bone levels at ≥12 months of follow-up (focused question 1), as well as on bone defect dimension (width/height) changes at re-assessment after ≥4 months (focused question 2). Only randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared different biomaterials for GBR were considered. A Bayesian network meta-analysis (NMA) was performed using a random-effects model. A ranking probability between treatments was obtained, as well as an estimation of the surface under the cumulative ranking value (SUCRA). Overall, whenever the biological principle of GBR was followed, regeneration occurred in a predictable way, irrespective of the type of biomaterial used. A lower efficacy of GBR treatments was suggested for initially large defects, despite the trend did not reach statistical significance. Regardless of the biomaterial employed, a certain resorption of the augmented bone was observed overtime. While GBR was shown to be a safe and predictable treatment, several complications (including exposure, infection, and soft tissue dehiscence) were reported, which tend to be higher when using cross-linked collagen membranes.

Harmonization of six quantitative SARS-CoV-2 serological assays using sera of vaccinated subjects

Background and aims

Vaccines, to limit SARS-CoV-2 infection, were produced and reliable assays are needed for their evaluation. The WHO produced an International-Standard (WHO-IS) to facilitate the standardization/comparison of serological methods. The WHO-IS, produced in limited amount, was never tested for reproducibility. This study aims at developing a reproducible and accessible working standard (WS) to complement the WHO-IS.

Materials and methods

Sera from vaccinated individuals were used to produce the WSs. The WHO-IS, the WSs and single serum samples (n = 48) were tested on 6 quantitative serological devices. Neutralization assays were performed for the 48 samples and compared with their antibody titers.

Results

The WS carry an antibody titer 20-fold higher than the WHO-IS. It was reproducible, showed both good linearity and insignificant intra- and inter-laboratory variability. However, the WSs behave differently from the WHO-IS. Analysis of the 48 samples showed that single correlation factors are not sufficient to harmonize results from different assays. Yet, all the devices predict neutralization activity based on the antibody titer.

Conclusions

A reproducible and highly concentrated WS, specific for IgG against SARS-CoV-2 Spike-glycoprotein was produced. Such characteristics make it particularly suited for the harmonization of commercially available assays and the consequent evaluation of post-vaccinated individuals.

Cardiac transplant vasculopathy treated by percutaneous coronary intervention

AIM

Cardiac transplant vasculopathy is a limit to long-term survival in heart transplantation (H-Tx) recipients. PTCA results in our H-Tx population were retrospectively analyzed.

METHODS

From November 1985 to May 2004, 767 patients underwent heart transplantation. All patients received immunosuppressive therapy with cyclosporine or tacrolimus, azathioprine, steroids and mycophenolate mofetil. Lymphocyte was administrated by 3-7 days course of either rabbit antithymocyte globulins or anti-lymphocyte globulins or by a 14 days course of OKT3. Coronary angiograms were performed every year and more frequently if graft vasculopathy was already diagnosed or suspected.

RESULTS

Fifty-two coronary artery lesions were treated during 42 percutaneous transluminal cardioangioplasty (PTCA)/stent procedures in 36 patients. Mean time since heart transplantation to PTCA was 80 +/- 27 months. Indication to PTCA was asymptomatic angiographic graft vasculopathy in 34 patients (94%) and acute myocardial infarction in 2 patients (6%). PTCA was performed on left anterior descending artery in 34 cases (65.4%), on circumflex artery in 10 cases (19.2%), on right coronary artery in 8 cases (15.4%). There were no procedure related deaths. None of the patients required emergency bypass surgery. Two patients had transient acute renal failure. Patient follow-up showed 10 deaths after 1 +/- 54 months from PTCA. Six died for progression of graft vasculopathy, three for cancer and one for gastrointestinal bleeding. Two patients underwent heart retransplantation after 20 and 107 months from the first procedure. Mean follow-up of the remaining patients is 78.3 +/- 50.3 months.

CONCLUSION

PTCA may represent a reasonable treatment for graft vasculopathy in selected heart transplant recipients.

Plaque composition in plexogenic and thromboembolic pulmonary hypertension: the critical role of thrombotic material in pultaceous core formation

BACKGROUND

Patients with pulmonary hypertension develop intimal plaques in large pulmonary arteries.

OBJECTIVE

To test the hypothesis that the composition of such plaques differs depending on whether the aetiology of the disease is thromboembolic or hypertensive.

DESIGN

Chronic thromboembolic and plexogenic pulmonary hypertension (primary and secondary (Eisenmenger syndrome)) were investigated. These are spontaneous human models and were used to examine the independent role of thrombus and hypertension in plaque composition.

SETTING

A national tertiary referral centre for lung transplantation and pulmonary thromboendoarterectomy.

PATIENTS

Thirty nine patients with chronic thromboembolic pulmonary hypertension who had undergone thromboendoarterectomy (n = 32) or lung transplantation (n = 7), 28 with plexogenic diseases (nine primary and 19 Eisenmenger), and three with Eisenmenger syndrome complicated by thromboembolic events.

INTERVENTIONS

The lung and thromboendoarterectomy samples were sectioned, stained with Movat pentachrome, and immunostained with antibodies for fibrin, platelets, inflammatory cells, smooth muscle cells, and erythrocyte membrane glycophorin A.

MAIN OUTCOME MEASURE

Composition of the plaques affecting large pulmonary arteries.

RESULTS

Two types of intimal lesion were distinguished in chronic thromboembolic pulmonary hypertension: fibrous plaques with angioneogenesis; and core-rich atherosclerotic plaques with pultaceous cores largely consisting of glycophorin immunoreactive material, with cholesterol clefts (61.5%), CD68 positive macrophages (84.6%), T lymphocytes (87%), and calcification (46.1%). The samples from the patients with Eisenmenger syndrome and thromboembolic complications had similar characteristics, whereas those from patients with uncomplicated primary pulmonary hypertension had core-free fibrous plaques, spotted with macrophages and T lymphocytes.

CONCLUSIONS

Chronic thromboembolic pulmonary hypertension is associated with atherosclerotic plaques with glycophorin-rich pultaceous cores, and plexogenic pulmonary hypertension with fibrous plaques. Thromboembolic material thus plays a critical role in the formation of pultaceous cores, of which erythrocyte membrane derived glycophorin is a major component.

Port access cardiac surgery

The port-access technique for cardiac surgery was recently developed at Stanford University in California as a less invasive method to perform some cardiac operations. The port-access system has been described in detail elsewhere. It is based on femoral arterial and venous access for cardiopulmonary bypass (CPB) and on the adoption of a specially designed triple-lumen catheter described originally by Peters, and subsequently modified and developed in the definitive configuration called the endoaortic clamp.

Arterial baroreflex modulation of heart rate in patients early after heart transplantation: lack of parasympathetic reinnervation

BACKGROUND

Orthotopic heart transplantation results in cardiac denervation. The presence of cardiac parasympathetic reinnervation in humans has been widely debated based on the application of differing indirect measures of autonomic control. However no attempt has been made to analyse the reflex heart rate response to baroreceptor stimulation whose occurrence is generally considered a reliable marker of the ability to activate cardiac vagal reflexes. This study tested the hypothesis that the presence of donor heart RR interval lengthening following phenylephrine induced blood pressure increase would be an index of parasympathetic reinnervation.

METHODS

Baroreflex sensitivity (BRS) was assessed in 30 patients (mean age 51+/-12 years) 1-24 months after heart transplantation carried out by the standard Lower-Shumway technique. In 6 patients the recipient atrium rate response (P-P interval) to baroreceptor stimulation by phenylephrine was also simultaneously determined by transesophageal recording.

RESULTS

None of the 30 patients showed prolongation of RR intervals in the donor heart. The average BRS value was -0.28+/-0.54 ms/mmHg (range -1.3-0.7 ms/mm Hg). In the 6 patients in whom BRS was obtained at both the recipient atrium (P-P) and donor heart (R-R) the changes were 7.6+/-5.7 ms/mm Hg and -0.38+/-0.58 ms/mm Hg respectively (p = 0.02), thus confirming that the absent RR interval lengthening in the donor heart is the consequence of efferent vagal fiber interruption.

CONCLUSIONS

The absence of any RR interval prolongation following phenylephrine induced baroreceptor stimulation demonstrates that vagal efferent reinnervation of the donor heart does not occur up to 24 months in patients operated via the standard Lower-Shumway procedure. It is also suggested that analysis of baroreceptor reflexes is a more specific method in the examination of cardiac parasympathetic reinnervation.

Effect of perfusion pH on rat lung viability of non-heart beating donors

OBJECTIVE

Non-heart beating donors could be an important source of lungs for transplantation. In prior experiments, trypan blue exclusion was used to assess the percentage of viable lung cells after different intervals following circulatory arrest. In this study, we assessed the importance of the trypan blue perfusate pH because in liver preservation studies, pH of the perfusate appears to be very important with the presence of a 'pH paradox'.

METHODS

Forty Sprague-Dawley rats (n = 5 each group) were sacrificed, left at room temperature, and ventilated with 100% O2 (tidal volume 0.01 cc/g, rate 30/min) for 4 or 8 h after death. Lungs were then flushed with 150 cc of trypan blue in Krebs-Heinseleit buffer via the pulmonary artery, then with 150 cc of fixative (2%) paraformaldehyde + 2% gluteraldehyde). The pH of the trypan blue solution was varied from 6.5 to 7.8. Lungs were sectioned, and cell viability was quantified based on exclusion of trypan blue.

RESULTS

Longer cadaver time was associated with less viability, but pH had no effect on viability. The results were similar in groups ventilated for the same period of time and then flushed with solutions at different pH (4 h, viability 80-84%; 8 h, viability 68-72%). Over the range investigated, the pH of the trypan blue solution had no impact on lung viability in non-heart beating donors and the lungs did not show the 'pH paradox'.

CONCLUSION

Lung tissue is not susceptible to the 'pH paradox' observed in liver preservation studies. Because more than 80% of lung cells are still viable 4 h after death if the lungs are ventilated with 100% O2 during the cadaveric period, retrieval and transplantation of cadaveric lungs may be feasible and might alleviate the paucity of lung donors.

Staged discharge out of hospital of the Novacor left ventricular assist system (LVAS) recipients

The mobility afforded by the wearable Novacor LVAS provides the possibility for the recipients to leave the hospital, with undoubted improvements in their quality of life. A staged program for discharging LVAS recipients from the hospital has been set up at the Policlinico San Matteo of Pavia together with the Rehabilitation Center of Montescano and Baxter Novacor Service support, in order to proceed smoothly towards patient's self sufficiency and to minimize any associated risk. The steps are: stay in the hospital ward, discharge to Rehabilitation Center and discharge to home. Several excursions with and without an LVAS team member are encouraged before final discharge to home. Simple criteria of eligibility must be fulfilled to move to the next step. Every move towards a reduced presence of specialized personnel includes an appropriate training of the patient and relatives and a technical checkout of the needed equipment. During the stay at the Rehabilitation Center primarily the physical training and psychological preparation are taken care of by means of tailored programs. When the patient is discharged to home, the check of patient condition is performed weekly at the Rehab Center, bloodwork and technical evaluation is assessed once every two weeks and technical inspections at home twice per year. Complications are reported as in hospital protocol. Control parameters of the LVAS are reported only in case of alarms or abnormal operation. Periodic review of patient training is performed during the check visits, mostly focused on how to address emergency situations. The hospital is responsible for providing one LVAS operator available on call (all hours). Up to date, 11 patients received an implant of LVAS, 9 of them with the wearable system. All of these 9 patients made excursions out of the hospital and 4 patients have successfully undergone the staged program, showing a satisfactory general condition and restoration to social life.

Human cytomegalovirus early infection, acute rejection, and major histocompatibility class II expression in transplanted lung. Molecular, immunocytochemical, and histopathologic investigations

The present study aimed to investigate the relationship between acute rejection and human cytomegalovirus (HCMV) infection, as well as the coexpression of HLA-DR and immediate-early (IE) viral antigens, in 143 transbronchial biopsies and bronchoalveolar lavage fluids of 32 lung transplant recipients. We investigated the occurrence of morphologically overt viral infection with conventional histopathology, the expression of IE antigens with single labeling immunohistochemistry, the coexpression of IE antigens and HLA-DR molecules with double labeling techniques, and the presence of viral IE genes with polymerase chain reaction. Histopathologic study showed overt viral infections (12.6%) in 18 of the 143 biopsies; 8 were in a context of pneumonia and 10 were localizations without surrounding inflammatory cells; immunohistochemistry showed IE viral antigen expression in 31 (21.67%); PCR detected viral IE genes in 73/143 lavage fluids and biopsies (51%). The double labeling immunohistochemical technique showed that most IE antigen-expressing, noncytopathic cells were either HLA-DR negative in areas without infiltrates, or HLA-DR positive in those areas where inflammatory infiltrates were consistent, in the absence of viral cytopathy, with acute rejection. The results indicate that, in transplanted lung, the frequency of morphologically occult HCMV infection (as detected by immunohistochemically and/or PCR) is much higher than that of morphologically overt viral infection. The occurrence of inflammatory infiltrates (consistent with acute rejection) around morphologically occult infected cells and the possible lack of inflammation around both early- and late-infected cells suggest that in biopsies with occult infection the infiltrates should be attributed to allograft reaction. This conclusion would be in keeping with the coexpression of HLA-DR and HCMV IE in infiltrate-rich biopsies that are consistent with acute rejection, as well as with the absence of HLA-DR expression in IE antigen-positive cells in infiltrate-free-areas.

Orthotopic heart transplantation with bicaval anastomosis

Images

Modified method for Novacor left ventricular assist device implantation

We have developed and applied in 7 cases an alternative "orthodromic" technique for Novacor left ventricular assist device implantation. After sternotomy, the pocket is tailored, dividing the insertion of the diaphragm to the lower ribs, for easier bleeding control. On cardiopulmonary bypass, the aorta is cross-clamped and cardioplegia administered. Apical cannulation is performed first on a dry, still field. The device is then easily deaired, with blood flowing in the physiologic direction. The aorta is declamped and the outflow conduit is anastomosed. Before the suture is tied, the final deairing is obtained. This technique allows extreme precision in apical cannulation, easier control of bleeding, and accurate deairing of the pump. The ischemic time is short and damage to the right ventricle negligible.

Demonstrable cardiac reinnervation after human heart transplantation by carotid baroreflex modulation of RR interval

BACKGROUND

After heart transplantation, respiration-synchronous fluctuations (0.18 to 0.35 Hz, high frequency [HF]) in RR interval may result from atrial stretch caused by changes in venous return, but slower fluctuations (0.03 to 0.15 Hz, low frequency [LF]) not due to respiration suggest reinnervation. In normal subjects, sinusoidal neck suction selectively stimulates carotid baroreceptors and causes reflex oscillations of RR interval.

METHODS AND RESULTS

To evaluate the presence of reinnervation, we measured the power of RR-LF and RR-HF in 26 heart transplant recipients and 16 control subjects before and during sinusoidal neck suction at 0.1 Hz and 0.20 Hz (similar to but distinct from that of controlled respiration, 0.25 Hz) and before and during administration of atropine or beta-blocker (esmolol hydrochloride) by spectral analysis. All transplant recipients showed small respiratory HF fluctuations. Nonrespiratory LF fluctuations were present in 13 of 26 transplant recipients and increased with months since transplantation (r = .53, P < .01). HF neck suction induced a 0.20-Hz component in all 16 control subjects and none of the 26 transplant subjects. LF neck suction increased RR-LF (from 0.73 +/- 0.20 to 1.30 +/- 0.26 ln ms2, P < .001), similar to but less than in control subjects (from 6.12 +/- 0.21 to 8.27 +/- 0.21 ln ms2, P < .001). Atropine reduced all fluctuations in control subjects and blocked the HF increase caused by 0.20-Hz neck suction but not the LF increase during 0.10-Hz stimulation. Neck suction-induced changes in LF fluctuations persisted after administration of atropine in transplant recipients but were attenuated by esmolol hydrochloride, suggesting sympathetic rather than vagal reinnervation.

CONCLUSIONS

The presence of baroreceptor-induced RR oscillations is evidence of functional, although incomplete, autonomic reinnervation.

Non-respiratory components of heart rate variability in heart transplant recipients: evidence of autonomic reinnervation?

1. Although the high-frequency fluctuations in R-R interval (respiratory sinus arrhythmia) observed in heart transplant recipients are not a reliable marker of reinnervation because of a previously shown direct mechanical effect of breathing, the presence of a non-respiration-related low-frequency oscillation reflects rhythms generated outside the heart, and thus could be neurally mediated. 2. To evaluate the presence of reinnervation, the spontaneous variability in R-R interval was investigated, supine and after passive tilting, in 23 heart transplant recipients (age 43 years, range 23-64 years) and in 25 normotensive control subjects by autoregressive spectral analysis of low- and high-frequency spontaneous fluctuations in R-R interval and respiration. The response of R-R interval to amyl nitrite inhalation was also evaluated in five heart transplant recipients and eight control subjects. 3. Detectable low-frequency oscillations, unrelated to respiration, were present in 13/23 heart transplant recipients, particularly in those who were transplanted at least 20 months earlier (11/14). The natural logarithm of the power of low-frequency fluctuations was markedly lower than in control subjects (0.75 +/- 0.21 versus 5.62 +/- 0.20 ms2, P < 0.001). The low-frequency but not the high-frequency fluctuations correlated with time since transplantation (r = 0.44, P < 0.05). The subjects with low-frequency fluctuations showed a sudden decrease in R-R interval with amyl nitrite linearly related to the decrease in mean blood pressure (r > or = 0.94). The slopes obtained in these heart transplant recipients were comparable (although of lower values) with those obtained in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiosarcoma of the heart: report of a case in a 9-year-old boy

A 9-year-old boy with a myocardiac angiosarcoma is described; the tumor was diagnosed by echocardiography and the boy underwent surgery followed by radio and chemotherapy. Death occurred 5 months after surgery, probably due to abdominal hemorrhage from metastases. The young age of the patient, the acute and reversible hepatic damage, the use of echocardiography for diagnosis and the possible role of the extracorporeal circulation in determining the metastases are emphasized.