Maximilian Pichlmaier

Bleeding management with fibrinogen concentrate targeting a high-normal plasma fibrinogen level: a pilot study

Background Bleeding diathesis after aortic valve operation and ascending aorta replacement (AV–AA) is managed with fresh-frozen plasma (FFP) and platelet concentrates. The aim was to compare haemostatic effects of conventional transfusion management and FIBTEM (thromboelastometry test)-guided fibrinogen concentrate administration. Methods A blood products transfusion algorithm was developed using retrospective data from 42 elective patients (Group A). Two units of platelet concentrate were transfused after cardiopulmonary bypass, followed by 4 u of FFP if bleeding persisted, if platelet count was ≤100×103 µl−1 when removing the aortic clamp, and vice versa if platelet count was >100×103 µl−1. The trigger for each therapy step was ≥60 g blood absorbed from the mediastinal wound area by dry swabs in 5 min. Assignment to two prospective groups was neither randomized nor blinded; Group B (n=5) was treated according to the algorithm, Group C (n=10) received fibrinogen concentrate (Haemocomplettan® P/Riastap, CSL Behring, Marburg, Germany) before the algorithm-based therapy. Results A mean of 5.7 (0.7) g fibrinogen concentrate decreased blood loss to below the transfusion trigger level in all Group C patients. Group C had reduced transfusion [mean 0.7 (range 0–4) u vs 8.5 (5.3) in Group A and 8.2 (2.3) in Group B] and reduced postoperative bleeding [366 (199) ml vs 793 (560) in Group A and 716 (219) in Group B]. Conclusions In this pilot study, FIBTEM-guided fibrinogen concentrate administration was associated with reduced transfusion requirements and 24 h postoperative bleeding in patients undergoing AV–AA.

Thromboelastometry-guided administration of fibrinogen concentrate for the treatment of excessive intraoperative bleeding in thoracoabdominal aortic aneurysm surgery

OBJECTIVE Thoracoabdominal aortic aneurysm operations are associated with extensive blood loss and high requirements for allogeneic blood product transfusion. We assessed the efficacy of intraoperative post-cardiopulmonary bypass administration of fibrinogen concentrate in elective thoracoabdominal aortic aneurysm surgery. METHODS In a retrospective group (group A, n = 12) of patients undergoing elective thoracoabdominal aortic aneurysm surgery, clinically relevant diffuse bleeding after weaning from cardiopulmonary bypass was treated with allogeneic blood products (platelet concentrates, followed by fresh frozen plasma) according to a predetermined algorithm. In a prospective group (group F, n = 6) a first therapy step with fibrinogen concentrate was added to the algorithm. The dose of fibrinogen concentrate was estimated by using thromboelastometric data (ROTEM FIBTEM). Before each step of hemostatic therapy, blood loss in the range of 60 to 250 g per 5 minutes was confirmed. RESULTS In group F, administration of 7.8 +/- 2.7 g of fibrinogen concentrate established hemostasis, completely avoiding intraoperative transfusion of fresh frozen plasma and platelet concentrates. Transfusion of blood products after cardiopulmonary bypass and during the 24 hours after surgical intervention was markedly lower in group F than in group A (2.5 vs 16.4 units; 4/6 patients in group F required no transfusion of blood products), as was 24-hour drainage volume (449 vs 1092 mL). Fibrinogen plasma levels, standard coagulation parameters, and hemoglobin and hematocrit values were comparable between the 2 groups on the first postoperative day. CONCLUSIONS FIBTEM-guided post-cardiopulmonary bypass administration of fibrinogen concentrate resulted in improved intraoperative management of coagulopathic bleeding in thoracoabdominal aortic aneurysm operations and reduced transfusion and 24-hour drainage volume.

Effects of fibrinogen concentrate as first-line therapy during major aortic replacement surgery: a randomized, placebo-controlled trial.

Background:Fibrinogen is suggested to play an important role in managing major bleeding. However, clinical evidence regarding the effect of fibrinogen concentrate (derived from human plasma) on transfusion is limited. The authors assessed whether fibrinogen concentrate can reduce blood transfusion when given as intraoperative, targeted, first-line hemostatic therapy in bleeding patients undergoing aortic replacement surgery. Methods:In this single-center, prospective, placebo-controlled, double-blind study, patients aged 18 yr or older undergoing elective thoracic or thoracoabdominal aortic replacement surgery involving cardiopulmonary bypass were randomized to fibrinogen concentrate or placebo, administered intraoperatively. Study medication was given if patients had clinically relevant coagulopathic bleeding immediately after removal from cardiopulmonary bypass and completion of surgical hemostasis. Dosing was individualized using the fibrin-based thromboelastometry test. If bleeding continued, a standardized transfusion protocol was followed. Results:Twenty-nine patients in the fibrinogen concentrate group and 32 patients in the placebo group were eligible for the efficacy analysis. During the first 24 h after the administration of study medication, patients in the fibrinogen concentrate group received fewer allogeneic blood components than did patients in the placebo group (median, 2 vs. 13 U; P < 0.001; primary endpoint). Total avoidance of transfusion was achieved in 13 (45%) of 29 patients in the fibrinogen concentrate group, whereas 32 (100%) of 32 patients in the placebo group received transfusion (P < 0.001). There was no observed safety concern with using fibrinogen concentrate during aortic surgery. Conclusions:Hemostatic therapy with fibrinogen concentrate in patients undergoing aortic surgery significantly reduced the transfusion of allogeneic blood products. Larger multicenter studies are necessary to confirm the role of fibrinogen concentrate in the management of perioperative bleeding in patients with life-threatening coagulopathy.

Ascending aortic cannulation in acute aortic dissection type A: the Hannover experience

OBJECTIVE The incidence of embolic events and of cerebral malperfusion in aortic dissection type A (AADA) must be viewed in the context of the existence of a number of possible cannulation techniques. Since femoral cannulation is thought to be associated with a higher risk of perfusion of the false lumen and retrograde embolization, techniques establishing antegrade flow may provide a better option. We describe herein our experience with ascending aortic cannulation in this special patient population. METHODS Between November 1999 and February 2006, 122 patients underwent operation for AADA with arterial access via the dissected ascending aorta. The aorta was cannulated at the site of the minimal distances of the dissected layers. Double purse-string sutures were used to support the cannula. Pressure monitoring in both radial arteries as well as bilateral cerebral oxygen saturation measurement helped to identify malperfusion after establishment of cardiopulmonary bypass. Aortic arch as well as aortic root surgery was performed, as dictated by the pathology. Selective antegrade cerebral perfusion and moderate hypothermia were used for brain and body protection. RESULTS Malperfusion occurred in three patients (2.5%). Hospital mortality was 15% for the entire cohort (18 patients). Permanent neurological dysfunction was detected in 15 patients (12%), whereas temporary neurological dysfunction occurred in 21 (17%). Total arch replacement was performed in 31 patients (25%). CONCLUSION Direct cannulation of the ascending aorta is an easy and safe method in patients with AADA. This technique, which also avoids retrograde flow in the downstream aorta, is an alternative to time-consuming axillary artery access.

Eight-year experience with cryopreserved arterial homografts for the in situ reconstruction of abdominal aortic infections

OBJECTIVE This study investigated short-term and long-term outcomes in patients with abdominal aortic infection (mycotic aneurysm, prosthetic graft infection, aortoenteric fistula) managed by total excision of the aneurysm or the infected vascular graft and in situ aortic reconstruction with a cryopreserved arterial homograft (CAH). METHODS From January 2000 to December 2008, 110 consecutive patients underwent CAH implantation for treatment of vascular infections. In 57 (52%), in situ revascularization of the abdominal aorta with Y-prosthesis constructed from CAHs was performed. Early outcome included 30-day mortality and the levels of daily blood markers (leucocytes, C-reactive protein, and platelets) during the postsurgical 10-day period. We reported long-term survival and freedom from reoperation rates, including all indications for reoperation. RESULTS Indications for operation were infected vascular graft in 31 patients (55%), aortodigestive fistulae in 11 (19%), nonruptured mycotic aneurysms in 4 (7%), and ruptured mycotic aneurysms of abdominal aorta in 11 (19%). In 39 of 57 patients (68%), the intraoperative specimens were positive for at least one microorganism, and Staphylococcus aureus was present in 14 (25%). In 32 patients (82%) with intraoperative specimens positive for microorganisms, there was no evidence of the intraoperatively detected microorganisms in the postoperative specimens (wound, blood culture, and drainage fluid). The peak value of leucocytes (13.7 +/- 4.4 x 10(3)/L) and C-reactive protein (200 +/- 75 mg/L) occurred on postoperative day 3. Platelets reached the lowest value on postoperative day 2 (178 +/- 67 x 10(9)/L). Median peak body temperature was 37.7 degrees +/- 0.6 degrees C. Thirty-day mortality was 9% (5 of 57 patients). Median follow-up was 36 months (range, 4-118 months); 3-year survival was 81%, and freedom from reoperation was 89%. Five patients (9%) required reoperation, in one patient each for postoperative bleeding, acute cholecystitis, homograft occlusion, homograft-duodenum fistula, and aneurysmal degeneration. No recurrence of infection was reported. CONCLUSION These results demonstrate an encouraging outcome after cryopreserved allograft implantation for the treatment of vascular infections in the abdominal aorta. The data represent a basis for future comparisons with other treatment modalities for vascular infections, including silver-coated prostheses and autogenous femoral veins.

Implantable defibrillator therapy for ventricular tachyarrhythmia in left ventricular assist device patients

Ventricular arrhythmias (VA) occur frequently after permanent left ventricular assist device (LVAD) implantation in end stage heart failure. Left ventricular assist device patients require rhythm control in contrast to patients with biventricular support. However, the rationale for implantable cardioverter‐defibrillator (ICD) utilization in LVAD patients remains unclear. This study investigated the safety and efficacy of primary prevention ICD therapy and the rate of appropriate ICD interventions in LVAD patients.

Fibrinogen concentrate reduces intraoperative bleeding when used as first-line hemostatic therapy during major aortic replacement surgery: results from a randomized, placebo-controlled trial.

OBJECTIVES We assessed whether fibrinogen concentrate as targeted first-line hemostatic therapy was more effective than placebo or a standardized transfusion algorithm in controlling coagulopathic bleeding in patients undergoing major aortic surgery. METHODS In this single-center, prospective, double-blind study, adults undergoing elective thoracic or thoracoabdominal aortic replacement surgery involving cardiopulmonary bypass were randomized to intraoperative fibrinogen concentrate (n = 29) or placebo (n = 32). Study medication was given if patients had clinically relevant coagulopathic bleeding, measured by 5-minute bleeding mass, after cardiopulmonary bypass removal, protamine administration, and surgical hemostasis. Fibrinogen concentrate dosing was individualized using the thromboelastometric FIBTEM test. If bleeding continued, a standardized transfusion algorithm was followed. In the placebo group, all 32 patients received 1 transfusion cycle of fresh-frozen plasma/platelets, and 30 patients required a second transfusion cycle; none of these patients received any other procoagulant therapy. Change in bleeding rate after treatment was compared using t tests. RESULTS Mean change in bleeding rate after fibrinogen concentrate was -48.3 g/5 min, compared with 0.4 g/5 min after placebo (P < .001), -16.1 g/5 min after 1 transfusion cycle (fresh-frozen plasma or platelets; P = .003), and -28.0 g/5 min after 2 transfusion cycles (fresh-frozen plasma and platelets; P = .11). Reductions in bleeding rate were greater for patients with higher bleeding rates before treatment, especially with fibrinogen concentrate. CONCLUSIONS FIBTEM-guided intraoperative hemostatic therapy with fibrinogen concentrate is more effective than placebo in controlling coagulopathic bleeding during major aortic replacement surgery. Fibrinogen concentrate is also more effective than 1 cycle of fresh-frozen plasma/platelets and is more rapid than--and at least as effective as--2 cycles of fresh-frozen plasma/platelets.

Elephant trunk procedure 27 years after Borst: what remains and what is new?

The treatment of complex aortic pathology involving both the ascending and descending aortic segments at the same time represents a surgical challenge, with high postoperative morbidity and mortality rates reported. Over the past 27 years, different open surgical and endovascular techniques have been introduced and applied in various two-stage- or one-stage approaches to such cases. Thus, in 1983, Hans Borst significantly changed the traditional two-stage approach by introducing his elephant trunk technique. Leaving a segment of Dacron prosthesis reaching into the descending aorta during the first stage, the second-stage replacement of the residual dilated descending aorta was made far easier. The presence of interval mortality between the two stages, the unaffected need for two large operations to complete aortic repair, and the general failure of some patients to return for the second-stage repair set the scene for the development of one-stage procedures, both open surgical or hybrid surgical and endovascular, such as the frozen elephant trunk. However, the size of the operation, on the one hand, and the risk of spinal cord injury and need for surgical or endovascular completion during follow-up, on the other, have dampened enthusiasm. Recently, the introduction of supra-aortic debranching and endovascular aortic arch stent-graft repair has yet extended treatment to high-risk patients unsuitable to the more aggressive surgery, but mid- and long-term follow-up results are lacking. The lack of randomization and the presence of procedural and complication-related limitations for each technique do not allow for definitive conclusions about the ideal procedure to treat complex aortic pathology. However, the technical revolution experienced over the past 27 years, along with the improvement in perioperative management, has produced outstanding morbidity and mortality results even in this challenging patient population, but the decision regarding which pathology correlates with what operation remains highly debated and dependent also on regional competence.

High prevalence of asymptomatic bacterial colonization of rhythm management devices

AIMS Recent work has been focused on causes of and risk factors for rhythm management device infections. The aim of this study was to elucidate whether patients may be asymptomatic carriers of bacteria on their rhythm management device, possibly allowing later manifestation of infection. METHODS AND RESULTS A total of 108 devices were changed for battery depletion between April 2005 and February 2006 in asymptomatic patients who were examined for evidence of bacterial DNA on the device and in the surrounding tissue using single strand conformation polymorphism analysis (SSCP). Follow-up was for 23.4 months. In 47.2% of the patients, bacterial DNA was demonstrated on the device, which had been in place for 64.1 months. The sequences identified bacterial strains that are untypical for clinical device infections. Staphylococci were demonstrated in only 3.7% of the patients and they became symptomatic within the observation interval; all others remained asymptomatic. The known risk factors for device infections did not correlate with the demonstration of bacterial DNA in this population. Common cohabitation was identified among the strains found. CONCLUSION A large proportion of patients carry bacteria on their pacemaker or implantable cardioverter defibrillator asymptomatically. The strains found differ from those commonly seen in clinically evident device infections. Common risk factors for device infection did not correlate with the presence of DNA.

Distal aortic surgery following arch replacement with a frozen elephant trunk.

OBJECTIVE The frozen elephant trunk technique allows the repair of concomitant aortic arch and proximal descending aortic pathology in a single stage by using a hybrid prosthesis consisting of a vascular graft with a distal stented end. There are patients, however, who will require a second distal operation despite this new technique due to progression of their aortic disease. It has been unclear whether the presence of the stented segment of the hybrid prosthesis results in unexpected technical difficulties or possibly advantages for further vascular reconstruction. METHODS Six patients out of our initial cohort of 39 treated with a hybrid prosthesis from 2001 through 2006 have since required an additional distal aortic reconstruction. Two received endoluminal stent grafts, four had extensive open replacements. RESULTS There was no 30-day mortality, one patient died on day 133 having been discharged from hospital of an unrelated MRSA septicaemia. Complete thrombosis of the proximally covered aneurysm or the false lumen had occurred in all patients so that the replacements reached from the end of the stented portion of the hybrid prosthesis to the desired distal level. The operative approach proved to be facilitated by the hybrid prosthesis in terms of the necessary exposure and operative trauma. Postoperative recovery was uneventful as related to the hybrid prosthesis with few pulmonary complications and at least comparable to contemporary results for second stage elephant trunk procedures. CONCLUSIONS The distal operative replacement of the aorta following a frozen elephant operation is safe and technically feasible. Early experience suggests that there is an advantage as compared to the conventional elephant technique in terms of intraoperative handling and postoperative recovery.