Honors & Awards
Magna Cum Laude for Outstanding Educational Presentation, Radiologic Society of North America (12/1/2015)
Dr. Scholl SURF Scholar, Mayo Clinic (2011)
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View details for Web of Science ID 000522979100406
View details for Web of Science ID 000522979100477
Objective: To estimate the diagnostic yield and efficacy of multiphase computed tomographic enterography (mpCTE) for suspected small bowel bleeding in routine clinical practice.Patients and Methods: All mpCTEs performed between January 1, 2006, and December 31, 2014, for suspected small bowel bleeding were included and classified by a gastroenterologist and an abdominal radiologist. The reference standard for a definitive diagnosis was balloon-assisted enteroscopic, angiographic, surgical, or pathologic results. Overall and lesion-specific diagnostic yield (DY), sensitivity, and positive predictive value were calculated. The relationship of mpCTE diagnosis and continued bleeding or iron supplementation was examined using logistic regression in patients with at least 1 year of follow-up.Results: We identified 1087 patients who had an initial mpCTE indication of small bowel bleeding. The overall DY was 31.6% (344 of 1087 patients; 95% CI, 29.0%-35.0%), higher for an indication of small bowel bleeding that was overt or occult with heme-positive stool vs occult with only iron-deficiency anemia (DY, 35.0% [170 of 486] and 35.3% [66 of 187] vs 26.1% [108 of 414]; P=.004 and P=.02, respectively). The highest sensitivity and positive predictive value were for small bowel masses (90.2% [55 of 61] and 98.2% [55 of 56], respectively). Higher risk of future bleeding and iron supplementation was seen with a negative result on mpCTE (odds ratio [OR], 1.91; 95% CI, 1.28-2.86), lack of surgical intervention (OR, 4.37; 95% CI, 2.31-8.29), or discrepant balloon-assisted enteroscopic findings (OR, 2.50; 95% CI, 1.03-6.09).Conclusion: Multiphase computed tomographic enterography has a higher rate of detection in patients with overt bleeding or heme-positive stool. The procedure provides actionable targets for further intervention and leads to substantially reduced rates of rebleeding in long-term follow-up.
View details for DOI 10.1016/j.mayocpiqo.2019.09.001
View details for PubMedID 31993562
View details for Web of Science ID 000460565900539
View details for Web of Science ID 000528619406362
PathogenicRYR2variants account for ?60% of clinically definite cases of catecholaminergic polymorphic ventricular tachycardia. However, the rate of rare benignRYR2variants identified in the general population remains a challenge for genetic test interpretation. Therefore, we examined the results of theRYR2genetic test among patients referred for commercial genetic testing and examined factors impacting variant interpretability.Frequency and location comparisons were made forRYR2variants identified among 1355 total patients of varying clinical certainty and 60?706 Exome Aggregation Consortium controls. The impact of the clinical phenotype on the yield ofRYR2variants was examined. Six in silico tools were assessed using patient- and control-derived variants.A total of 18.2% (218/1200) of patients referred for commercial testing hosted rareRYR2variants, statistically less than the 59% (46/78) yield among clinically definite cases, resulting in a much higher potential genetic false discovery rate among referrals considering the 3.2% background rate of rare, benignRYR2variants. Exclusion of clearly putative pathogenic variants further complicates the interpretation of the next novelRYR2variant. Exonic/topologic analyses revealed overrepresentation of patient variants in exons covering only one third of the protein. In silico tools largely failed to show evidence toward enhancement of variant interpretation.Current expert recommendations have resulted in increased use ofRYR2genetic testing in patients with questionable clinical phenotypes. Using the largest to date catecholaminergic polymorphic ventricular tachycardia patient versus control comparison, this study highlights important variables in the interpretation of variants to overcome the 3.2% background rate that confoundsRYR2variant interpretation.
View details for PubMedID 29453246
We sought to examine the incidence and predictors of arrhythmias and sudden cardiac death (SCD) after Fontan operation.Arrhythmias and SCD have been reported following operations for congenital heart disease, but the incidence and risk factors have not been well defined in patients after a Fontan operation.We reviewed records of all patients who had a Fontan operation from 1973 to 2012 (n?=?1052) at our institution. A questionnaire was mailed to patients who were not known to be deceased at the initiation of the study. Late arrhythmias were classified as bradyarrhythmias or tachyarrhythmias requiring treatment >30 days after operation.We included 996/1052 (95%) patients with no arrhythmia diagnosis prior to Fontan. Overall 10-, 20-, and 30-year freedom from arrhythmias was 71%, 42%, and 24%, respectively. Of 864 patients who survived >30 days after Fontan, 304 (35%) had atrial flutter, 161 (19%) had atrial fibrillation, 108 (13%) had atrial tachycardia, 37 (4%) had reentrant supraventricular tachycardia, 40 (5%) had ventricular tachycardia, and 113 (13%) had sinus node dysfunction. Predictors of late arrhythmias included an atriopulmonary Fontan, age at operation (>16 years) or atrial arrhythmias postoperatively. During follow-up, 52/1052 (5%) patients had SCD, with 51 having documentation available; 8 patients died suddenly within 30 days and the remaining 43 had an average time to SCD of 6.9?±?6.7 years (median was 3.8 years). Arrhythmias were documented in 28/43 (65%) patients prior to SCD. Predictors of SCD included atrioventricular valve replacement and post-bypass Fontan pressures >20 mm Hg; preoperative sinus rhythm was protective.Arrhythmias and SCD are significant concerns among Fontan patients and specific risk factors may warrant closer follow-up and earlier consideration for therapy.
View details for DOI 10.1111/chd.12401
View details for PubMedID 27545004
The objective of our study was to compare a flavored beverage containing a thickening agent for enterography with a low-Hounsfield-value barium suspension for side effects, taste, subjects' willingness to repeat the drinking protocol, and small-bowel distention.The following five drinking protocols were administered to 10 volunteers: 1000 mL of flavored beverage followed by 350 mL of water, 1500 mL of flavored beverage, 900 mL of low-Hounsfield-value barium suspension followed by 450 mL of water, 1350 mL of low-Hounsfield-value barium suspension followed by 150 mL of water, and 1500 mL of water. MR images were obtained 50 and 60 minutes after initiation of drinking. Subjects completed a questionnaire evaluating the side effects, the taste of the drink, and their willingness to repeat the drinking protocol. Reviewers assigned scores evaluating small-bowel distention and ranked the examinations in order of preference.There was no significant difference in nausea or vomiting among the protocols (p = 0.20 and 0.42, respectively), but larger volumes of flavored beverage and low-Hounsfield-value barium suspension resulted in more cramping and diarrhea (p = 0.001 and 0.002, respectively). The taste of the low-Hounsfield-value barium suspension was rated the worst (p < 0.0001). The subjects' willingness to repeat the drinking protocol was highest for the 1000 mL of flavored beverage or water alone (p < 0.05). There were no significant differences in subjective small-bowel distention except that water was rated the worst by two of the three readers (p < 0.02). There was no significant difference in the diameter of the most dis-tended small bowel for any segment or reader (p > 0.23).A flavored beverage containing a thickening agent has a similar side effect profile and results in equivalent small-bowel distention compared with a low-Hounsfield-value barium suspension, but subjects rate taste and their willingness to repeat the drinking protocol higher for this new agent.
View details for DOI 10.2214/AJR.15.15260
View details for Web of Science ID 000374860500020
View details for PubMedID 26998661
We reviewed records of all patients with an initial Fontan operation or revision from 1973 to 2012 at our institution (n = 1,138); 195 patients had postoperative liver data available. Cirrhosis was identified by histopathology or characteristic findings on imaging with an associated diagnosis of cirrhosis by a hepatologist. Of 195 patients with biopsy or imaging, 10-, 20-, and 30-year freedom from cirrhosis was 99%, 94%, and 57%, respectively. There were 40 of 195 patients (21%) diagnosed with cirrhosis (mean age at Fontan 10.7 ± 8 years). On multivariate analysis, hypoplastic left heart syndrome was associated with increased risk of cirrhosis (n = 2 of 16, p = 0.0133), whereas preoperative sinus rhythm was protective (p = 0.009). Survival after diagnosis of cirrhosis was 57% and 35%, at 1, and 5 years, respectively. The cause of death was known for 9 patients (5 multiorgan failure, 2 liver failure, and 2 heart failure). In conclusion, there is an incremental occurrence of cirrhosis after the Fontan, which should be considered when designing follow-up protocols for patients after Fontan operation.
View details for DOI 10.1016/j.amjcard.2015.11.014
View details for Web of Science ID 000369194200023
View details for PubMedID 26704027
We performed a retrospective review of outcomes after heart transplantation during long-term follow-up of a surgical cohort of 1138 Fontan patients who were followed at the Mayo Clinic. Follow-up information was obtained from medical records and a clinical questionnaire that was mailed to patients not known to be deceased at the initiation of the study. Forty-four of 1138 Fontan patients with initial or subsequent evaluation at Mayo had cardiac transplantation between 1988 and 2014 (mean age at transplantation was 23.2 ± 12 yr, median was 19.8 yr; mean interval between Fontan and transplantation was 13.0 ± 7.7 yr, median was 13.1 yr). Two patients had combined organ transplantation (one heart-lung, one heart-liver). Twelve of the 44 (27%) patients had PLE prior to transplantation. There was no difference in post-bypass Fontan pressures or incidence of late reoperations for AVV repair/replacement between transplanted and non-transplanted patients. There were 16 (36%) deaths in the transplantation cohort; seven occurred within 30 days of transplantation. Overall one, five, 10, and 15 yr post-transplantation survival was 80%, 72%, 69%, and 55%, respectively. Although this is a challenging group of patients, intermediate-term results suggest that cardiac transplantation remains a reasonable option for patients with a failed Fontan circulation.
View details for DOI 10.1111/petr.12753
View details for PubMedID 27397767
The feasibility and safety of pregnancy after the Fontan operation is not well understood. We sought to determine contraception practices and early and late outcomes of pregnancy after the Fontan operation.We performed a retrospective review of medical records to identify women of childbearing age from the Mayo Clinic Fontan database. A follow-up questionnaire was mailed to all patients not known to be deceased at the time of study. Patients with available contraception and pregnancy data were included in the study.Of the 138 women with available contraception data, 44% used no contraception, 12% each used barrier methods, combination hormone therapy or sterilization, 8% used Depo-Provera, 7% had intrauterine devices, 4% had a partner with a vasectomy and 1% used progestin pills. Six women had thrombotic complications (only one using oral contraceptives). Thirty-five women had pregnancy data available. Prior to the Fontan operation there were 10 pregnancies (8 miscarriages, 2 therapeutic abortions, and no live births). After the Fontan operation there were 70 pregnancies resulting in 35 miscarriages (50%), 29 live births (41%), and 6 therapeutic abortions (9%). There were no maternal deaths during pregnancy. During long-term follow up (26 ± 6 years since the Fontan), 1 death, and 1 cardiac transplant occurred. Mean gestational age of the newborns (n = 22/29) was 33.1 ± 4.0 weeks; mean birth weight (n = 20/29) was 2086 ± 770?g. There was 1 neonatal death because of prematurity and two children were born with congenital heart disease (one patent ductus arteriosus and one membranous ventricular septal defect).Pregnancy after the Fontan operation is associated with a high rate of miscarriages, preterm delivery, and low birth weight. Further studies are needed to identify specific variables influencing risk stratification of pregnancy in this patient population.
View details for DOI 10.1111/chd.12291
View details for Web of Science ID 000371241800010
View details for PubMedID 26239864
There are limited long-term, single-cohort, follow-up studies available about patients after the Fontan operation.This study sought to determine the long-term outcome of all patients who had a Fontan operation at the Mayo Clinic.Records of all patients who had a modified Fontan operation between 1973 and 2012 were reviewed. A follow-up questionnaire was mailed to all patients alive at the time of the study.Overall, 10-, 20-, and 30-year survival for 1,052 patients was 74%, 61%, and 43%, respectively. Factors associated with decreased overall or late survival in multivariate analysis included pre-operative diuretic use, longer cardiopulmonary bypass time, operation prior to 1991, atrioventricular valve (AVV) replacement at the time of Fontan operation, elevated post-bypass Fontan (>20 mm Hg) or left atrial (>13 mm Hg) pressures, prolonged chest tube drainage (>21 days), post-operative ventricular arrhythmias, renal insufficiency, and development of protein-losing enteropathy (PLE). Pre-operative and intraoperative sinus rhythm were associated with improved survival. Long-term survival was similar for patients regardless of ventricular morphology. The most common reoperations were pacemaker insertion/revision in 212 patients (20%), Fontan revision/conversion in 117 patients (11%), and AVV repair/replacement in 66 patients (5%). Clinically significant late atrial or ventricular arrhythmias occurred in 468 patients (44%). Ninety-five patients (9%) developed PLE, and 5-, 10-, and 20-year survival after diagnosis of PLE was 50%, 35%, and 19%, respectively.As the surgical techniques for the Fontan operation have changed over the last 40 years, survival has improved. However, development of PLE and arrhythmias and the need for reoperation during long-term follow-up pose significant management challenges.
View details for DOI 10.1016/j.jacc.2015.07.065
View details for Web of Science ID 000363329200009
View details for PubMedID 26449141
Localized excision combined with radiation and chemotherapy represents the current standard of care for recurrent breast cancer. However, in certain conditions a forequarter amputation may be employed for these patients.We present a patient with recurrent breast cancer who had a complicated treatment history including multiple courses of chemotherapy, radiation, and local surgical excision. With diminishing treatment options, she opted for a forequarter amputation in an attempt to limit the spread of cancer.In our patient the forequarter amputation was utilized as a last resort to slow disease progression after she had failed multiple rounds of chemotherapy and received maximal radiation. Unfortunately, while she had symptomatic relief in the short-term, she had cutaneous recurrence of metastatic adenocarcinoma within 2 months of the procedure. In comparing this case with other reported forequarter amputations, patients with non-metastatic disease showed a mean survival of approximately two years. Furthermore, among patients who had significant pain prior to surgery, all patients reported pain relief, indicating a significant palliative benefit. This seems to indicate that our patient's unfortunate outcome was anomalous compared to that of most patients undergoing forequarter amputation for recurrent breast cancer.Forequarter amputation can be judiciously used for patients with recurrent or metastatic breast cancer. Patients with recurrent disease without evidence of distant metastases may be considered for curative amputation, while others may receive palliative benefit; disappointingly our patient achieved neither of these outcomes. In the long term, these patients may still have significant psychological problems.
View details for DOI 10.1016/j.ijscr.2015.04.018
View details for PubMedID 25898339
The neural control of hand movement involves coordination of the sensory, motor, and memory systems. Recent studies have documented the motor coordinates for hand shape, but less is known about the corresponding patterns of somatosensory activity. To initiate this line of investigation, the present study characterized the sense of hand shape by evaluating the influence of differences in the amount of grasping or twisting force, and differences in forearm orientation. Human subjects were asked to use the left hand to report the perceived shape of the right hand. In the first experiment, six commonly grasped items were arranged on the table in front of the subject: bottle, doorknob, egg, notebook, carton, and pan. With eyes closed, subjects used the right hand to lightly touch, forcefully support, or imagine holding each object, while 15 joint angles were measured in each hand with a pair of wired gloves. The forces introduced by supporting or twisting did not influence the perceptual report of hand shape, but for most objects, the report was distorted in a consistent manner by differences in forearm orientation. Subjects appeared to adjust the intrinsic joint angles of the left hand, as well as the left wrist posture, so as to maintain the imagined object in its proper spatial orientation. In a second experiment, this result was largely replicated with unfamiliar objects. Thus, somatosensory and motor information appear to be coordinated in an object-based, spatial-coordinate system, sensitive to orientation relative to gravitational forces, but invariant to grasp forcefulness.
View details for DOI 10.1523/JNEUROSCI.5158-10.2011
View details for Web of Science ID 000288160500025
View details for PubMedID 21389230