The use of gelatin-resorcin-formalin glue in acute aortic dissection type A

Water-Mediated On-Demand Detachable Solid-State Adhesive of Porous Hydroxyapatite for Internal Organ Retractions

Novel adhesives for biological tissues offer an advanced surgical approach. Here, the authors report the development and application of solid-state adhesives consisting of porous hydroxyapatite (HAp) biocompatible ceramics as novel internal organ retractors. The operational principles of the porous solid-state adhesives are experimentally established in terms of water migration from biological soft tissues into the pores of the adhesives, and their performance is evaluated on several soft tissues with different hydration states. As an example of practical medical utility, HAp adhesive devices demonstrate the holding ability of porcine livers and on-demand detachability in vivo, showing great potential as internal organ retractors in laparoscopic surgery.

How to test adhesive strength: a biomechanical testing for aortic glue used in type a dissection repair

OBJECTIVES

The aim of this study was to develop a method to quantify the peel force in an in vitro model simulating repair of ascending aortic dissections with tissue glue (Bioglue).

METHODS

This study adapted an adhesive T-Peel test for the determination of the peel strength of adhesives by measuring the peeling force of a T-shaped bonded tissue. Measurements were performed on iatrogenic dissected ascending porcine aorta, which has been repaired with Bioglue using different pressure levels. Four conditions were tested: zero sample pressure according to the manufacturer's recommendation (n = 10), low (504 Pa; n = 11), moderate pressure (1711 Pa; n = 24) and pressure applied by a round shaped vascular 'Borst clamp' (1764 Pa; n = 23). Non-parametric one-way analysis of variance was applied for statistical significance.

RESULTS

The median peel force (lower quartile, upper quartile) of aortic samples increased depending on the applied pressure: [no pressure 0.030 N/mm (0.016, 0.057), low pressure 0.040 N/mm (0.032, 0.070) and moderate pressure 0.214 N/mm (0.050, 0.304)]. Samples pressurized with the Borst clamp reached 0.078 N/mm (0.046, 0.152), which was comparable to the peel force of the unpeeled controls [0.107 N/mm (0.087, 0.124)]. Compared to samples without pressure, Bioglue with the application of the Borst clamp (P = 0.021) and with moderate pressure (P = 0.0007) performed significantly better.

CONCLUSIONS

The novel T-Peel test offers an attractive method to test tissue glues in defined in vitro environments. Bioglue peel force increased with pressure on the aortic sample in contrast to low or no pressure as per the manufacturer's recommendation. Modifying current recommended use may aid in increasing effectiveness of this approach.

Utilization of By-Products from Livestock: Study on the Mechanical and Thermal Properties of Biodegradable Containers Made with Pork Skin Gelatin Polymer

This study aimed to develop a biodegradable container made of pork gelatin. Gelatin was extracted from pork skin by hot water at 80 °C, and containers were prepared by adding eggshell powder (20%) as a pore agent, and walnut powder (0.08 wt%; PEW1, 0.14 wt%; PEW2) to improve hardness. The blends were molded for each experiment and dried at 30 °C for 24 h, at 40 °C for 16 h, and at 121 °C for 16 h. The containers were analyzed with respect to morphological (SEM; scanning electron microscope), mechanical (tensile strain and stress), and thermal (DSA; differential scanning calorimetry and TGA; thermogravimetric analysis) properties, as well as biodegradability. SEM investigation showed a smoother surface for PEW1 than for PEW2. The tensile stress of PEW2 (37.86 MPa) was significantly higher than that of PEW1 (28.40 MPa), and the melting enthalpies were 137.60 J/g (PEW1) and 309.60 J/g (PEW2). TGA showed similar properties, but PEW2 contained more lignin; therefore, its decomposition temperature was higher. The PEW1 and PEW2 containers were completely biodegraded after approximately 7 and 11 weeks, respectively. Walnut shell powder increased the hardness, but slowed the biodegradation process. The applications of this biodegradable container are short-lived products such as food packaging.

Self-adhering implantable device of titanium: Enhanced soft-tissue adhesion by sandblast pretreatment

Self-adhering implantable devices, which can be immobilized inside the bodies without suturing nor organic glues, made of metallic biomaterials would be optimal devices for preventing device-related complications such as device migration after implantation. We reported previously that acid-treated commercially-pure titanium (CpTi) adhered directly and immediately on hydrous non-keratinized soft tissues. Herein, we investigated the influence of sandblasting as pretreatment for acid-treated CpTi to increase its soft tissue adhesiveness. First, the effects of sandblasting conditions (i.e., pressure, distance and time) were investigated in terms of the sandblasted surface area and the degree of deformation (i.e., internal stress formation) of CpTi films. The effect of the sandblasting on the immediate soft tissue adhesion of acid-treated CpTi was investigated using an ex vivo shear adhesion test with mouse dermal tissues. The optimal sandblasting pretreatment remarkably improved the soft tissue adhesion strength of acid-treated CpTi (102 ± 19 kPa) compared with the non-sandblasted counterparts (41 ± 2 kPa). Finally, the CpTi adhesive was applied for immobilizing a near field communication (NFC) device in vivo, and was shown to have strong immediate adhesion to muscle fascia.

A decade of surgical therapy in an all-comer cohort with type A aortic dissection

BACKGROUND

We reported on a decade of aortic surgery for type A aortic dissection to assess surgical techniques employed and outcomes over time in an all-comer analysis of a mid-size university cardiosurgical center.

METHODS

From 2009 to 2018, 283 patients (189 males and 94 females, mean age 62 years, range 30-85 years), who underwent surgical therapy for type A aortic dissection in our institution were included in a retrospective statistical analysis.

RESULTS

Among all the patients, 55.5% of them were hemodynamically stable, 10.3% came in intubated. A neurological deficit was present in 18.9% of cases, extremity malperfusion was noted in 17.4%, and abdominal malperfusion detected in 8.2%. The extent of the aortic dissection corresponded to DeBakey type I in 88% of cases, a thoracoabdominal involvement was seen in 64%. In 51.9% of patients, only the ascending aorta replaced, another 40.6% of patients had proximal arch replacement too. A separate stent placement into the descending aorta was achieved in 13.4% of patients, during surgery (5.7%) or thereafter (7.7%). Overall survival to discharge was 79.5%. Most frequent complications were stroke and paralysis (15.2%), but only visceral malperfusion (OR 9.0) and heart failure mandating ECMO therapy (OR 29.5) were associated with significantly increased mortality.

CONCLUSIONS

Surgery for type A aortic dissection is still challenging. Along with the refinement of surgical techniques, the indication for the various procedures has moved from a simplified general strategy to a more individualized concept.

Aortic Root Reconstruction with TachoSil Fibrin Sealant Patch in Acute Type A Aortic Dissection

Purpose: We propose a novel technique for reconstruction of the dissected aortic root with the use of TachoSil fibrin sealant patch.

Methods: Patients with acute type A aortic dissection involving the aortic root were included. Appropriately prepared TachoSil fibrin sealant patch was placed between the dissected layers of the aortic root to achieve their durable fusion. Thus, the false lumen was eliminated, and the anatomical and functional structure of the aortic wall was restored.

Results: In all, 13 patients mean aged 57 ± 10.3 years underwent surgery for acute type A aortic dissection with the use of TachoSil fibrin sealant patch. All patients survived the surgery. The mean follow-up time was 30.8 ± 16.4 months. Follow-up computed tomography angiography (CTA) scans confirmed no aortic root dissection in all patients.

Conclusions: This technique ensures durable restoration of the aortic wall structure, eliminates the secondary aortic valve regurgitation, and allows for the preservation of patients’ native aortic valve.

Anti-Adhesive, Platelet Gathering Effects of c-RGD Modified Poly(p-dioxanone-co-l-Phe) Electrospun Membrane and Its Comprehensive Application in Intestinal Anastomosis

Intestinal resection and anastomosis are performed in over a million people with various bowel diseases annually. Excessive fibrosis and anastomotic site leakage are the main complications of anastomosis surgery, despite great improvements in operative technique and equipment in recent years. In this study, cRGD modified poly(p-dioxanone-co-l-Phe) (PDPA) membranes are designed and applied in intestinal anastomosis to simultaneously solve the two aforementioned complications. cRGD is modified onto PDPA membranes through both physical absorption and π-π accumulation between d-Phe of cRGD and l-Phe of PDPA. Although cRGD modification enhanced the biocompatibility of PDPA membranes, cRGD modified PDPA membrane suppresses fibroblast proliferation both in vitro and in vivo as a result of degradation and subsequent release of fibroblast suppressive l-Phe from PDPA. Meanwhile, platelets are entrapped by cRGD modified PDPA membranes through the specific binding of cRGD and platelet GP_IIbIIIa . cRGD modified PDPA membranes are applied in rat intestinal anastomosis, and both adhesion and stenosis are successfully prevented at anastomotic sites. At the same time, bursting pressure, which represents healing intensity at anastomotic sites, is promoted. The gathering and activation of platelets on PDPA membranes induce secretion of autologous PDGF and VEGF to facilitate angiogenesis and subsequent healing of anastomotic sites.

Valve-Sparing Aortic Root Replacement as First-Choice Strategy in Acute Type a Aortic Dissection

Background: Although, in theory, valve-sparing aortic root replacement (David procedure) is an ideal surgical option for acute aortic dissection type A (AADA) it is usually not regarded as the first-choice treatment due to the emergency setting and the relative complexity of the procedure. Here, we report the results of a consecutive, single-surgeon series of 45 AADA patients with the David procedure as first-choice treatment strategy. Methods and Results: Between September 2009 and July 2013 a total of 49 patients with AADA were consecutively operated by the same surgeon at our institution. The David procedure was the treatment of choice for the proximal aorta unless aortic valve pathology or critical preoperative patient status advocated against it. Median follow-up was 5.0 years (CI95%, 4.0-6.0). Out of the 45 patients included in this study the David procedure was performed in 28 patients (62.2%), while in 17 patients (37.8%) an alternative surgical strategy had to be pursued. Although X-clamping (168.5 ± 41.7 vs. 110.3 ± 51.1 min; p = 0.001), cardiopulmonary bypass (CPB) (245.0 ± 62.4 vs. 211.8 ± 123 min; p = 0.029) and total operation time (383.8 ± 88.5 vs. 312.8 ± 144.8; p = 0.047) were significantly longer in the David-group as compared to the non-David group, there was no difference in major complication rate as well as 30-day (17.9 vs. 23.5%; p = 0.645) and 5-year mortality (28.6 vs. 35.3%) between groups. Conclusions: This small series indicates that the David procedure may be safe and feasible as a primary surgical treatment strategy for AADA.

Effects of albumin/glutaraldehyde glue on healing of colonic anastomosis in rats

AIM

To evaluate the effect of local surgical adhesive glue (albumin/glutaraldehyde-Bioglue) on the healing of colonic anastomoses in rats.

METHODS

Forty Albino-Wistar male rats were randomly divided into two groups, with two subgroups of ten animals each. In the control group, an end-to-end colonic anastomosis was performed after segmental resection. In the Bioglue group, the anastomosis was protected with extraluminar application of adhesive glue containing albumin and glutaraldehyde. Half of the rats were sacrificed on the fourth and the rest on the eighth postoperative day. Anastomoses were resected and macroscopically examined. Bursting pressures were calculated and histological features were graded. Other parameters of healing, such as hydroxyproline and collagenase concentrations, were evaluated. The experimental data were summarized and computed from the results of a one-way ANOVA. Fisher’s exact test was applied to compare percentages.

RESULTS

Bursting pressures, adhesion formation, inflammatory cell infiltration, and collagen deposition were significantly higher on the fourth postoperative day in the albumin/glutaraldehyde group than in the control group. Furthermore, albumin/glutaraldehyde significantly increased adhesion formation, inflammatory cell infiltration, neoangiogenesis, and collagen deposition on the eighth postoperative day. There was no difference in fibroblast activity or hydroxyproline and collagenase concentrations.

CONCLUSION

Albumin/glutaraldehyde, when applied on colonic anastomoses, promotes their healing in rats. Therefore, the application of protective local agents in colonic anastomoses leads to better outcomes.

Biocompatible nanostructured solid adhesives for biological soft tissues

Over the past few years, the development of novel adhesives for biological soft tissue adhesion has gained significant interest. Such adhesives should be non-toxic and biocompatible. In this study, we synthesized a novel solid adhesive using nanostructured hydroxyapatite (HAp) and evaluated its physical adhesion properties through in vitro testing with synthetic hydrogels and mouse soft tissues. The results revealed that HAp-nanoparticle dispersions and HAp-nanoparticle-assembled nanoporous plates showed efficient adhesion to hydrogels. Interestingly, the HAp plates showed different adhesive properties depending upon the shape of their nanoparticles. The HAp plate made up of 17nm-sized nanoparticles showed an adhesive strength 2.2times higher than that of the conventional fibrin glue for mouse skin tissues.

STATEMENT OF SIGNIFICANCE

The present study indicates a new application of inorganic biomaterials (bioceramics) as a soft tissue adhesive. Organic adhesives such as fibrin glues or cyanoacrylate derivatives have been commonly used clinically. However, their limited biocompatibility and/or low adhesion strength are some drawbacks that impair their clinical application. In this study, we synthesized a novel solid adhesive with biocompatible and biodegradable HAp nanoparticles without the aid of organic molecules, and showed a rapid and strong adhesion of mouse soft tissues compared to conventional fibrin glues. Given the importance of wet adhesion in biomedicine and biotechnology applications, our results will help not only in developing an efficient approach to close incised soft tissues, but also in finding novel ways to integrate soft tissues with synthetic hydrogels (such as drug reservoirs).

Evolution of surgical therapy for Stanford acute type A aortic dissection

Acute type A aortic dissection (AcA-AoD) is a surgical emergency associated with very high morbidity and mortality. Unfortunately, the early outcome of emergency surgical repair has not improved substantially over the last 20 years. Many of the same debates occur repeatedly regarding operative extent and optimal conduct of the operation. The question remains: are patients suffering from too large an operation or too small? The pendulum favoring routine aortic valve resuspension, when feasible, has swung towards frequent aortic root replacement. This already aggressive approach is now being challenged with the even more extensive valve-sparing aortic root replacement (V-SARR) in selected patients. Distally, open replacement of most of the transverse arch is best in most patients. The need for late aortic re-intervention has not been shown to be affected by more extensive distal operative procedures, but the contemporary enthusiasm for a distal frozen elephant trunk (FET) only seems to build. It must be remembered that the first and foremost goal of the operation is to have an operative survivor; additional measures to reduce late morbidity are secondary aspirations. With increasing experience, true contraindications to emergency surgical operation have dwindled, but patients with advanced age, multiple comorbidities, and major neurological deficits do not fare well. The endovascular revolution, moreover, has spawned innovative options for modern practice, including ascending stent graft and adaptations of the old flap fenestration technique. Despite the increasingly complex operations and ever expanding therapies, this life-threatening disease remains a stubborn challenge for all cardiovascular surgeons. Development of specialized thoracic aortic teams and regionalization of care for patients with AcA-AoD offers the most promise to improve overall results.

When and how to replace the aortic root in type A aortic dissection

Management of aortic root pathology during repair of acute type A aortic dissection (TAAD) requires a comprehensive evaluation of the patient's anatomy, demographics, comorbidities and physiologic status at the time of emergent operative intervention. Surgical options include conservative repair of the root (CRR) (with or without replacement of the aortic valve), replacement of the native valve and aortic root using a composite valve-conduit and valve sparing root replacement (VSRR). The primary objective of this review is to provide data for surgeons to aid in their decision-making process regarding management of the aortic root during repair of TAAD. No time or language restrictions were imposed and references of the selected studies were checked for additional relevant citations. Multiple retrospective reviews have demonstrated equivalent operative mortality between aortic root repair and replacement during TAAD. There is a higher incidence of aortic root reintervention with aortic root repair compared to aortic root replacement (ARR). Experienced, high-volume aortic centers have demonstrated the safety of VSRR in young, hemodynamically stable patients presenting with TAAD. In conclusion, aortic root repair can safely be performed in the vast majority of patients with TAAD. Despite the increased surgical complexity, ARR does not increase operative mortality and improves the freedom from root reintervention. VSRR can be performed in highly selected populations of patients with TAAD with durable mid-term valve function.

Modified Sandwich Technique for Acute Aortic Dissection

We describe a new method for aortic anastomosis in the repair of acute type A aortic dissection. The anastomosis site is prepared with the adventitial inversion technique, which converts a dissected aorta into a conduit lined with tough adventitia. The end is reinforced with felt strip outside and anastomosed with interrupted everting mattress and running sutures, resulting in complete hemostasis. This modified sandwich technique will likely be useful for the surgical treatment of acute aortic dissection.

Comparison of Left Ventricular Volume and Ejection Fraction and Frequency and Extent of Aortic Regurgitation After Operative Repair of Type A Aortic Dissection Among Three Different Surgical Techniques

Differences in recurrence rate of aortic regurgitation (AR) and extent of left ventricular (LV) remodeling across the different surgical options in patients operated for type A aortic dissection remain unknown. The present evaluation compared the AR recurrence rate and changes in LV volumes and systolic function in valve-sparing aorta replacement (VSAR), supracoronary ascending aorta replacement (SCAR), and aortic valve and aorta replacement (AVAR). A total of 97 patients (58 ± 12 years, 62% men) with acute type A aortic dissection who underwent VSAR (n = 24), SCAR (n = 43), or AVAR (n = 30) were evaluated. Changes in LV volumes and function between postoperative and follow-up were compared using linear mixed models. Postoperative AR grades were not significantly different between groups. However, after median follow-up of 47 months, AR grade ≥2 was significantly more often observed in SCAR (55%) and VSAR (25%) compared to AVAR (0%, p <0.001). LV volumes remained stable in VSAR and AVAR but increased significantly in SCAR (LV end-diastolic volume: from 99 ± 4 to 131 ± 6 ml; p <0.001; LV end-systolic volume: from 49 ± 3 to 66 ± 5 ml; p = 0.002). In patients with recurrent AR grade ≥2 at follow-up, LV volumes increased, whereas patients without recurrent AR did not show significant LV dilatation. In conclusion, patients with acute type A aortic dissection who underwent SCAR or VSAR showed more frequently AR grade ≥2 recurrence compared to AVAR. However, only patients who underwent SCAR experienced adverse LV remodeling at follow-up. Recurrence of AR grade ≥2 was associated with adverse LV remodeling.

Acute aortic dissection involving the root: operative and long-term outcome after curative proximal repair

OBJECTIVES

The aim of the study was to evaluate operative and long-term results after surgery of acute aortic dissection involving the root, in which the proximal repair consisted of curative resection of all dissected aortic sinuses and was performed using either valve-sparing root repair or complete root replacement with a valve conduit.

METHODS

Between August 2002 and March 2013, 162 consecutive patients (mean age 63 ± 14 years) underwent surgery for acute type A aortic dissection. Eighty-six patients with an involvement of the aortic root underwent curative surgery of the proximal aorta consisting of valve-sparing root repair (n = 54, 62.8%) or complete valve and root replacement using composite valve grafts (n = 32, 37.2%). In patients with root repair, all dissected aortic walls were resected and root remodelling using the single patch technique (n = 53) or root repair with valve reimplantation (n = 1) was performed without the use of any glue. All perioperative data were collected prospectively and retrospective statistical examination was performed using univariate and multivariate analyses.

RESULTS

The mean follow-up was 5.2 ± 3.5 years for all patients (range 0-12 years) and 6.1 ± 3.3 years for survivors. The 30-day mortality rate was 5.8% (5 patients), being considerably lower in the repair sub-cohort (1.9 vs 12.5%). The estimated survival rate at 5 and 10 years was 80.0 ± 4.5 and 69.1 ± 6.7%, respectively. No patient required reoperation on the proximal aorta and/or aortic valve during the follow-up time and there were only two valve-related events (both embolic, one in each group). Among those patients with repaired valves, the last echocardiography available showed no insufficiency in 40 and an irrelevant insufficiency (1+) in 14.

CONCLUSIONS

Curative repair of the proximal aorta in acute dissection involving the root provides favourable operative and long-term outcome with very low risk of aortic complications and/or reoperations, regardless if a valve-sparing procedure or replacement with a valve conduit is used. Valve-sparing surgery is frequently suitable, providing excellent outcome and very high durability.

Intractable ventricular fibrillation: post ascending aortic dissection repair

Ascending aortic dissection is a life threatening surgical emergency and carries high peri-operative mortality. Various biological adhesive materials are commonly used in such a surgery to enhance strengthening of separated layers of aortic wall. Despite of extensive use, embolization of the glue material remains a feared complication. Here we are describing a case where BioGlue embolized down the left main stem and resulted in refractory ventricular arrhythmia and hemodynamic instability.

Enhanced bonding strength of hydrophobically modified gelatin films on wet blood vessels

The bonding behavior between hydrophobically modified alkaline-treated gelatin (hm-AlGltn) films and porcine blood vessels was evaluated under wet conditions. Hexanoyl (Hx: C₆), decanoyl (Dec: C₁₀), and stearyl (Ste: C₁₈) chlorides were introduced into the amino groups of AlGltn to obtain HxAlGltn, DecAlGltn, and SteAlGltn, respectively, with various modification percentages. The hm-AlGltn was fabricated into films and thermally crosslinked to obtain water-insoluble films (t-hm-AlGltn). The 42% modified t-HxAlGltn (t-42HxAlGltn) possessed higher wettability than the 38% modified t-DecAlGltn (t-38DecAlGltn) and the 44% modified t-SteAlGltn (t-44SteAlGltn) films, and the t-42HxAlGltn film showed a high bonding strength with the blood vessel compared with all the hm-AlGltn films. Histological observations indicated that t-42HxAlGltn and t-38DecAlGltn remained on the blood vessel even after the bonding strength measurements. From cell culture experiments, the t-42HxAlGltn films showed significant cell adhesion compared to other films. These findings indicate that the Hx group easily interpenetrated the surface of blood vessels and effectively enhanced the bonding strength between the films and the tissue.

Fibrin sealant patch for repair of acute type a aortic dissection

INTRODUCTION

The use of glues to repair disrupted tissue during acute type-A aortic dissection (TAD) surgery may be discontinuous, and cause embolization and cell necrosis. We report a method of fibrin sealant patch (FSP) to reinforce dissected aortic tissue with a collagen double layer coated with fibrinogen/thrombin on either side (TachoSil®; Takeda, Konstanz, Germany).

METHODS

In 12 patients (seven male, 66.9 ± 11.7 years) with acute TAD we performed FSP of the intima-media disruption at the proximal and distal anastomosis of the aorta. We analyzed the perioperative course and echocardiographical, radiological, and clinical outcomes up to one year. Additionally, we investigated the adhesive potential of the FSP in vitro.

RESULTS

In vitro, the adhesive strength of the FSP was 60 N/cm(2). In-hospital mortality was 8.3% (n = 1), recovery was satisfactory with no major neurologic events, mean ICU stay was 13.6 ± 6.0 days, mean hospital stay was 20.7 ± 4.4 days. A total of 7.0 ± 2.6 RBC, 3.4 ± 1.5 platelets, and 8.0 ± 4.3 FFP were transfused. One-year survival was 83.3%. In 6/6 DeBakey II dissections the intimal tear was completely resected, in 2/6 DeBakey I dissections the false lumen in the descending aorta completely collapsed. No redissections and no relevant aortic valve insufficiencies were seen during follow-up.

CONCLUSION

This analysis shows that FSP using a collagen matrix double layer coated with fibrinogen/thrombin is feasible, safe, and effective in repairing the dissected aortic tissue. It results in continuous reinforcement of aortic tissue and completely avoids the need for conventional glues.

In vitro evaluation of tissue adhesives composed of hydrophobically modified gelatins and disuccinimidyl tartrate

The effect of the hydrophobic group content in gelatin on the bonding strength of novel tissue-penetrating tissue adhesives was evaluated. The hydrophobic groups introduced into gelatin were the saturated hexanoyl, palmitoyl, and stearoyl groups, and the unsaturated oleoyl group. A collagen casing was employed as an adherend to model soft tissue for the in vitro determination of bonding strength of tissue adhesives composed of various hydrophobically modified gelatins and disuccinimidyl tartrate. The adhesive composed of stearoyl-modified gelatin (7.4% stearoyl; 10Ste) and disuccinimidyl tartrate showed the highest bonding strength. The bonding strength of the adhesives decreased as the degree of substitution of the hydrophobic groups increased. Cell culture experiments demonstrated that fluorescein isothiocyanate-labeled 10Ste was integrated onto the surface of smooth muscle cells and showed no cytotoxicity. These results suggest that 10Ste interacted with the hydrophobic domains of collagen casings, such as hydrophobic amino acid residues and cell membranes. Therefore, 10Ste-disuccinimidyl tartrate is a promising adhesive for use in aortic dissection.

A case of ascending aortic pseudoaneurysm in a patient with aortic replacement

A 59-year-old man with a history of ascending aorta replacement for an aortic dissection using gelatin-resorcin-formalin glue at age of 50 years presented with paroxysmal nocturnal dyspnea. An echocardiogram showed severe aortic regurgitation associated with aortic root enlargement. Chest computed tomography showed that the ascending aorta was dilated and a pseudoaneurysm was observed around the implanted prosthetic graft. Upon opening the ascending aorta, we found that the posterior wall of the proximal anastomotic portion of the implanted graft was ruptured. After replacement of the aortic root with a composite graft and reconstruction of the orifices of the right and left coronary arteries, total arch replacement by the separated graft technique was performed. The postoperative course was uneventful.

Evidence, lack of evidence, controversy, and debate in the provision and performance of the surgery of acute type A aortic dissection

Acute type A aortic dissection is a lethal condition requiring emergency surgery. It has diverse presentations, and the diagnosis can be missed or delayed. Once diagnosed, decisions with regard to initial management, transfer, appropriateness of surgery, timing of operation, and intervention for malperfusion complications are necessary. The goals of surgery are to save life by prevention of pericardial tamponade or intra-pericardial aortic rupture, to resect the primary entry tear, to correct or prevent any malperfusion and aortic valve regurgitation, and if possible to prevent late dissection-related complications in the proximal and downstream aorta. No randomized trials of treatment or techniques have ever been performed, and novel therapies-particularly with regard to extent of surgery-are being devised and implemented, but their role needs to be defined. Overall, except in highly specialized centers, surgical outcomes might be static, and there is abundant room for improvement. By highlighting difficulties and controversies in diagnosis, patient selection, and surgical therapy, our over-arching goal should be to enfranchise more patients for treatment and improve surgical outcomes.

Valve-Sparing Aortic Root Stabilization in Acute Type a Aortic Dissection

Composite replacement is the standard approach for repair of acute type A aortic dissection involving the aortic root. Reimplantation or remodeling procedures have become valve-sparing alternatives. We developed a new and simple technique to stabilize the aortic root. A Dacron graft is attached outside the native aortic cylinder, and incised twice vertically to create openings corresponding to the right and left coronary ostia. Thus the entire graft covers the native aortic root cylinder from the outside, and the native aortic valve and coronary ostia do not need to be reimplanted. From 2002 to 2007, this technique was applied in 14 patients (8 male) with a mean age of 71 years (range, 34-83 years). Four patients died within 30 days; 3 had been hemodynamically unstable with ventilator and inotropic support preoperatively. Echocardiography showed normal function of the preserved aortic valve, without regurgitation, in all patients. This technique is an alternative valve-sparing method for stabilization of the aortic root in patients with acute type A aortic dissection.

Autologous glue: part of the sticky mystery unraveled

OBJECTIVE

The aim of the study was to evaluate the safety and efficacy of an autologous surgical tissue adhesive.

METHODS

Autologous glue was made out of canine concentrated plasma proteins mixed with 7.5% glutaraldehyde. Tensile strength and cytotoxicity of the autologous glue were tested. In a dog model, 8 transectioned iliac arteries were reanastomosed by using the animal's glue as the sole fixation method. After 120 days, all animals were angiographically controlled for patency and killed for histologic and immunohistochemical examination of the anastomosis.

RESULTS

The autologous glue showed sufficient tensile strength (557 +/- 135 N/mm2). The elasticity of the glue is influenced by variations of concentrations in both proteins and glutaraldehyde. Glutaraldehyde remained cytotoxic, even at low concentrations of 2.5%. All operative procedures were successful. Angiographs performed before animal death showed all but 1 vessel to be patent and showed manifest compression signs in 3 anastomoses. Histological examination revealed only a foreign-body reaction adjacent to the surface of the glue. The autologous glue does not trigger any immune response on immunochemistry. Because fibroblastic neo-endothelial lining was near to normal, potential glutaraldehyde leaching does not seem too harmful for the vascular juncture in the dog model.

CONCLUSIONS

Autologous glutaraldehyde glue has been used successfully as a vascular adhesive. In contrast to our previous studies with heterologous glue, we did not find a fierce acute inflammatory reaction indicating immune triggering. Nevertheless, glutaraldehyde remains a cytotoxic cross-linker. It is yet not known whether autologous glutaraldehyde glue can be used safely in clinical practice.

Late Complications of Gelatin-Resorcin-Formalin Glue in the Repair of Acute Type A Aortic Dissection

BACKGROUND

During surgical treatment for acute type A aortic dissection, gelatin-resorcin-formalin glue is generally applied and its efficacy has been reported. However, some late complications that are potentially associated with this glue have also been reported. In the present study, we reviewed our experiences of treatment for acute type A aortic dissection and late complications that occurred in the anastomotic site, which needed a reoperation.

METHODS

From October 1994 to August 2005, 68 patients underwent emergency surgery for acute type A aortic dissection. Gelatin-resorcin-formalin glue was applied to 56 (82.4%) of these patients at one or both of the distal and proximal anastomosis sites.

RESULTS

Eight (11.8%) patients died in hospital within 30 days after the operation, among which two patients already had cerebral complications prior to the surgery. There were five late deaths from causes unrelated to cardiac events. Five patients developed an aortic pseudoaneurysm at the anastomotic site and underwent a late reoperation. All of these patients had been treated with gelatin-resorcin-formalin glue during the previous operation. Histologic examination of the resected aortic wall after the reoperation revealed tissue necrosis, severe local inflammation, and organization of old thrombi at the site of the glue application.

CONCLUSIONS

Late complications after the use of gelatin-resorcin-formalin glue may occur with a certain amount of risk, suggesting its toxicity for aortic tissue. Therefore, proper use of this glue and close follow-up of the patients are strictly required.

A novel synthetic tissue-adhesive hydrogel using a crosslinkable polymeric micelle

We prepared a novel tissue-adhesive hydrogel by using a polymeric micelle consisting of an aldehyde-terminated poly(ethylene glycol)-poly(D,L-lactide) (PEG-PLA) block polymer. A Schiff base is chemically formed between the amino groups in a polyallylamine and the aldehyde groups on the surface of polymeric micelles. The hydrogel was formed in approximately 2 s when the polymeric micelle solution and polyallylamine solution are mixed in vitro. The hydrogel was rapidly formed in vivo, and it adhered to a tissue surface. Our novel tissue-adhesive hydrogel creates no risk of infectious contaminations, because it consists of only synthetic materials. Further, PEG and PLA are known to be biocompatible and noncytotoxic. The results obtained in the present study show that a hydrogel prepared by the formation of a Schiff base between aldehyde and amine groups will potentially address the need for novel tissue-adhesive materials.

Remodeling or reimplantation for valve-sparing aortic root surgery?

BACKGROUND

Valve-sparing operations are gaining increasing acceptance; however, there is an ongoing discussion about the technique-specific indications. We present our experience with a follow-up of 123 months.

METHODS

Between July 1993 and July 2005, 164 consecutive patients were operated on using the remodeling (group A, n = 96) or reimplantation technique (group B, n = 68). Fifty-seven patients presented with acute type A dissection. Aortic regurgitation was present in 84%. Follow-up was 54.7 +/- 28 in group A and 48.4 +/- 37.3 months in group B.

RESULTS

After urgent operations, 4 patients died in each group, but none died after elective surgery. Late mortality was 8% in group A and 4% in group B. Seven patients of group A and 1 in group B required reoperation. Echocardiographic follow-up of reoperation-free survivors showed that 3 patients (all group A, 1.3%) had aortic regurgitation of more than grade II. Root diameter, valve pressure gradient, and valve orifice area were comparable. No gross thromboembolic or bleeding events occurred.

CONCLUSIONS

Aortic valve-sparing operations can provide acceptable long-term results in both techniques. Particular care to the annulus in the remodeling technique and different prosthesis designs in the reimplantation technique may overcome the intrinsic problems of each procedure.

Use of BioGlue in Aortic Surgery: Proper Application Techniques and Results in 92 Patients

BACKGROUND

Surgery for pathology of the proximal aorta requires aortic wall reconstruction, re-approximation of the graft to native vessels, and potentially root replacement and valve resuspension or replacement. The purpose of this study is to describe proper application techniques and the results obtained with the adjunctive use of BioGlue Surgical Adhesive in this challenging patient population.

METHODS

Between August 1998 and June 2002, 92 consecutive patients underwent ascending/arch repairs, ascending/root repairs, Ross procedures, or ascending/arch repairs with a concomitant Ross procedure using BioGlue as an adjunct for anastomotic hemostasis.

RESULTS

Twenty-six patients (28.3%) in this series required no postoperative blood products. The mortality rate for this single-surgeon series was 3.3%. No device-related complications were observed. The incidence rate for postoperative pseudoaneurysm formation was 3.3%.

CONCLUSIONS

This series demonstrates the safety and effectiveness of BioGlue as a hemostatic adjunct in proximal aortic surgery. Use of the product helped to facilitate a minimal reliance on blood products and a low mortality rate.

Albumin-glutaraldehyde bioadhesive ("Bioglue") for prevention of postoperative complications after stapled hemorrhoidopexy: a randomized controlled trial

BACKGROUND

Hemorrhoidopexy using the circumferential stapler is an established method for surgical treatment of patients with prolapsing hemorrhoids. Despite its advantages, complications such as anal canal stenosis, hemorrhage and anastomosis leak with eventual intrapelvic sepsis can cause serious postoperative problems. The aim of this study was to evaluate the utility of a surgical adhesive, the biological albumin-glutaraldehyde glue "Bioglue", in reduction of these postoperative complications.

PATIENTS AND METHODS

Between January 2002 and November 2004, 200 patients undergoing stapled hemorrhoidopexy were enrolled in a prospective, randomized clinical trial. One hundred patients were randomly assigned to the control group; the study group consisted of 100 patients who received Bioglue in the mucosa anastomosis area. All patients received standardized postoperative analgesic, laxative and antibiotic treatment. We then evaluated the two groups for postoperative complications (after surgery and 6 months postoperatively).

RESULTS

From the control group (no Bioglue application), two patients presented with anal stenosis, two with hemorrhage, three had anastomosis leak and one had thrombosis, whereas none of the patients from the Bioglue group had any of these complications. Both groups had patients with severe postoperative pain (3 each) and fecal incontinence (1 patient each). The overall difference in the number of complications in the two groups was statistically significant (p < 0.05).

CONCLUSION

In this first study using Bioglue in patients undergoing circumferential stapled hemorrhoidopexy we have shown that application of the glue is effective in reducing postoperative complications.

Late Complications Following Surgery for Type A Acute Aortic Dissection Using Gelatin-Resorcin-Formaldehyde Glue: Report of Two Cases

Gelatin-resorcin-formaldehyde (GRF) glue has been widely applied during operations for acute aortic dissection (AAD). At our institution, GRF glue was applied in 40 patients who underwent surgical procedures for AAD from 1995, two of whom needed a reoperation because of the development of a redissection and/or a pseudoaneurysm at the anastomotic sites. The operative findings and histological examinations suggested that the application of GRF glue during the initial operations might be related to the development of a redissection and/or a pseudoaneurysm.

Long-Term Results After 27 Years of Surgical Treatment of Acute Type A Aortic Dissection

BACKGROUND

This study investigates the determinants of long-term outcome and modalities of late death after surgical treatment of acute type A dissection.

METHODS

Between 1974 and 2001, 315 consecutive patients were operated on for acute type A aortic dissection. Operative mortality was 22.9%. A series of 243 survivors of surgical treatment were followed up for as long as 27 years. Endpoints were death, cardiovascular reoperation, and neurologic events. Median follow-up was 4.5 years. Follow-up was 99.6% complete.

RESULTS

Cumulative survival of discharged patients was 96.4% +/- 1.3%, 67.7% +/- 4.7%, and 39.4% +/- 12.0% at 1, 10, and 20 years, respectively. During follow-up, 47 patients died. Cause of death was cardiac failure in 7, hemorrhage due to rupture of the distal aorta in 7, stroke in 4, respiratory insufficiency in 4, sepsis in 3, malignancy in 2, and unknown in 20 patients. Multivariate analysis revealed advanced patient age and postoperative hemodialysis as perioperative indicators of late death (p < 0.05). Freedom from cardiovascular reoperation was 90.7% +/- 2.0% at 1 year, 60.9% +/- 5.1% at 10 years and 41.9% +/- 15.0% at 20 years. A total of 58 patients required 86 cardiovascular reoperations; aortic root or ascending aorta replacement was performed in 20, distal ascending aorta and arch replacement in 13, descending aorta replacement in 6, thoracoabdominal aorta replacement in 7, abdominal aorta replacement in 7, and miscellaneous reoperations in 6 patients. Multivariate analysis revealed male sex and left coronary artery dissection as significant determinants for late cardiovascular reintervention (p < 0.05). Cumulative incidence of stroke after 20 years was 3.8%.

CONCLUSIONS

Acute type A dissection represents an emergency situation with acceptable long-term results for discharged survivors of surgical treatment.