Abstract 099: Prevalence of Headaches in Patients with Fibromuscular Dysplasia: A Report from the US Registry for FMD

Introduction: Fibromuscular dysplasia (FMD) is a polyvasculopathy that may result in aneurysm or dissection in affected arterial beds. A common symptom of FMD is headache (HA). The purpose of this study is to describe and compare characteristics of FMD patients with (w/HA) and without headaches (wo/HA) in the current US Registry for FMD.

Method: Data regarding demographics, family history, medical history, and vascular beds affected in patients with FMD were collected from the US Registry for FMD between 2009 and 2016. Patients with complete HA data were included, and data were compared between patients w/HA and wo/HA as reported at time of registry enrollment.

Results: Of the 1,433 patients in the registry, 1,251 (87.3%) had complete HA data. Most were female (94.1%), with a mean age of 56.0±12.4. A history of HA was reported in 844 (67.5%) patients and 54.2% reported a HA at least weekly. No difference in gender distribution was seen between HA groups. Patients w/HA were younger at the time of FMD diagnosis (50.6±11.8 years v 58.0±13.8 years, p<0.001) and were less likely to have a history of HTN (66.8% v 74.8%, p=0.004), hyperlipidemia (36.9% v 47.2%, p=0.004), or renal failure (2.6% v 5.7%, p=0.009). Patients w/HA were more likely to have a history of aneurysm or dissection in the extracranial carotid, intracranial, or vertebral arteries (aneurysm: 13.0% v 7.2% p=0.003; dissection: 25.1% v 8.3%, p<0.001). No differences in extracranial carotid, intracranial, or vertebral FMD involvement between patients w/ and w/o HA were seen when those with history of aneurysm or dissection of those arteries were excluded (71.2% v 66.8%, p=0.20). Headache patients more often reported a history of depression (25.1% v 16.5%, p=0.01) and anxiety (28.3% v 18.0%, p=0.003).

Conclusion: More than half of FMD patients experience HAs, most on an at least weekly basis. FMD patients with HA tended to be younger, and more likely to have extracranial carotid, intracranial, or vertebral disease as well as aneurysm and dissection. Depression and anxiety was also more common in FMD patients with HA. Further research is needed to classify the types of headaches being experienced as well as effective management strategies.

Mechanism of endonuclease cleavage by the HigB toxin

Bacteria encode multiple type II toxin-antitoxin modules that cleave ribosome-bound mRNAs in response to stress. All ribosome-dependent toxin family members structurally characterized to date adopt similar microbial RNase architectures despite possessing low sequence identities. Therefore, determining which residues are catalytically important in this specialized RNase family has been a challenge in the field. Structural studies of RelE and YoeB toxins bound to the ribosome provided significant insights but biochemical experiments with RelE were required to clearly demonstrate which residues are critical for acid-base catalysis of mRNA cleavage. Here, we solved an X-ray crystal structure of the wild-type, ribosome-dependent toxin HigB bound to the ribosome revealing potential catalytic residues proximal to the mRNA substrate. Using cell-based and biochemical assays, we further determined that HigB residues His54, Asp90, Tyr91 and His92 are critical for activity in vivo, while HigB H54A and Y91A variants have the largest effect on mRNA cleavage in vitro Comparison of X-ray crystal structures of two catalytically inactive HigB variants with 70S-HigB bound structures reveal that HigB active site residues undergo conformational rearrangements likely required for recognition of its mRNA substrate. These data support the emerging concept that ribosome-dependent toxins have diverse modes of mRNA recognition.

Comparison of Quality of Life Perceived by Patients with Bioprosthetic versus Mechanical Valves after Composite Aortic Root Replacement

Objective: To assess whether postoperative quality of life (QOL) for composite aortic root replacement patients differs according to whether it is based on the use of mechanical valves or bioprosthetic valves. Methods: The study included 146 consecutive patients who underwent composite aortic root replacement at our institution from January 2010 to April 2014 with bioprosthetic (34.9%, n = 51) and mechanical (65.1%, n = 95) valves. Patient-perceived QOL was measured by administering the Short Form (SF)-36v2 Health Survey and a series of supplemental questions to further evaluate valve-specific differences. Final survey participation (n = 121) included 82.9% of the qualifying patients, and involved 76.5% (39/51) of those with bioprosthetic valves and 86.3% (82/95) of those with mechanical valves. Reasons for not completing the survey included 5 expired patients (3.4%), 1 lost due to a language barrier (0.7%), 6 who refused to participate (4.1%) and 13 who were lost to follow-up (8.9%). The mean follow-up time was 32 months (range 4-56 months). Results: Patients in the bioprosthetic valve group were older (mean age 67.5 ± 13.6 years) and included more females (25.6% or 10/39) than those in the mechanical valve group (mean age 56.6 ± 12.0 years; 11.0% or 9/82 were female). No significant differences were found between the bioprosthetic and mechanical valve groups for any QOL aspects scored by the SF-36v2 survey. All 8 domains and 2 summary scales comprising the QOL evaluation were above national norms calculated using gender- and age-matched, norm-based scoring for a standard national average of 50. The supplemental questions indicated satisfaction with each valve type despite characteristics that were of concern to patients. In the mechanical valve group, 90.2% (74/82) reported that the audible valve click was not troublesome, 85.4% (70/82) that taking a blood thinner regularly did not affect daily life and 81.7% (67/82) that blood testing for anticoagulation therapy was not troublesome. Conclusions: Receiving a tissue or a mechanical valve does not directly affect postoperative QOL. Answers to supplemental questions suggest that prior concerns with mechanical valves do not affect patients in the commonly anticipated negative manner. The preconception of a heavy QOL burden for mechanical composite grafts is contradicted by this study.