The Value of Pharmacogenomics for White and Indigenous Americans after Kidney Transplantation

BACKGROUND

There is a paucity of evidence to inform the value of pharmacogenomic (PGx) results in patients after kidney transplant and how these results differ between Indigenous Americans and Whites. This study aims to identify the frequency of recommended medication changes based on PGx results and compare the pharmacogenomic (PGx) results and patients' perceptions of the findings between a cohort of Indigenous American and White kidney transplant recipients.

METHODS

Thirty-one Indigenous Americans and fifty White kidney transplant recipients were studied prospectively. Genetic variants were identified using the OneOme RightMed PGx test of 27 genes. PGx pharmacist generated a report of the genetic variation and recommended changes. Pre- and post-qualitative patient surveys were obtained.

RESULTS

White and Indigenous American subjects had a similar mean number of medications at the time of PGx testing (mean 13 (SD 4.5)). In the entire cohort, 53% received beta blockers, 30% received antidepressants, 16% anticoagulation, 47% pain medication, and 25% statin therapy. Drug-gene interactions that warranted a clinical action were present in 21.5% of patients. In 12.7%, monitoring was recommended. Compared to the Whites, the Indigenous American patients had more normal CYP2C19 (p = 0.012) and CYP2D6 (p = 0.012) activities. The Indigenous American patients had more normal CYP4F2 (p = 0.004) and lower VKORC (p = 0.041) activities, phenotypes for warfarin drug dosing, and efficacy compared to the Whites. SLC6A4, which affects antidepressant metabolism, showed statistical differences between the two cohorts (p = 0.017); specifically, SLC6A4 had reduced expression in 45% of the Indigenous American patients compared to 20% of the White patients. There was no significant difference in patient perception before and after PGx.

CONCLUSIONS

Kidney transplant recipients had several drug-gene interactions that were clinically actionable; over one-third of patients were likely to benefit from changes in medications or drug doses based on the PGx results. The Indigenous American patients differed in the expression of drug-metabolizing enzymes and drug transporters from the White patients.

Clinical Outcomes and Histological Patterns in Oxalate Nephropathy due to Enteric and Nonenteric Risk Factors

INTRODUCTION

Current knowledge of risk factors and renal histologic patterns of oxalate nephropathy (ON) not due to primary hyperoxaluria (PH) has been limited to small case series and case reports. Thus, we analyzed and compared clinical risk factors, histologic characteristics, and renal outcomes of patients with biopsy-confirmed ON among a cohort of patients with enteric and nonenteric risk factors.

METHODS

A clinical data repository of native kidney pathology reports from 2009 to 2020 at all Mayo Clinic sites was used to identify 421 ON cases.

RESULTS

After excluding cases in transplanted kidneys or due to PH, 64 cases remained. Enteric risk factors were present in 30 and nonenteric in 34. Roux-en-Y gastric bypass (17) and pancreatic insufficiency (6) were most common in the enteric hyperoxaluria group. In the nonenteric group, vitamin C (7) and dietary oxalate (7) were common, while no apparent risk was noted in 16. Acute kidney injury (AKI) stage III at the time of diagnosis was present in 60%, and 40.6% required dialysis. Patients in the nonenteric group had more interstitial inflammation (p = 0.01), and a greater number of tubules contained intratubular calcium oxalate (CaOx) crystals (p = 0.001) than the nonenteric group. Patients in the enteric group were more likely to have baseline chronic kidney disease (CKD) (p = 0.02) and moderate-to-severe tubulointerstitial fibrosis and atrophy (IFTA) (OR 3.49, p = 0.02). After a median follow-up of 10 months, 39% were dialysis dependent, 11% received a kidney transplant, and 32% died. On univariate analysis, >10 tubules with CaOx crystals, baseline CKD, and AKI requiring dialysis correlated with the risk of dialysis, transplant, or death. On multivariate analysis, only AKI requiring dialysis correlated with adverse renal outcomes.

CONCLUSION

This is the largest cohort study of ON not due to PH. Histologic features differ in patients with enteric versus nonenteric risks. Patients in the enteric group are more likely to have baseline CKD and significant IFTA, while patients in the nonenteric group were more likely to have a greater number of tubules with CaOx crystals and corresponding interstitial inflammation. AKI requiring dialysis at the time of diagnosis was the single most significant predictor of adverse renal outcome.

Abnormal vascular physiology in the lower extremities as a risk factor for ischemic stroke and mortality

CONTEXT

Peripheral artery disease (PAD) is highly prevalent in the general population, affecting up to 25% of patients 55 years of age or older. There is a known association with acute ischemic stroke, but limited large cohort studies exist pertaining to the relationship between PAD severity and incident ischemic stroke.

OBJECTIVES

To evaluate the risk of incident ischemic stroke and mortality along the spectrum of low and elevated ankle brachial index (ABI) measurement.

METHODS

We performed a retrospective extraction of ABI data of all adult patients who underwent lower extremity physiology study for any indication from January 1, 1996 to June 30, 2018 in the Mayo Clinic health system. PAD was categorized into severe, moderate, mild, and borderline based on ABI measurements and poorly compressible arteries (PCA). These were compared with normal ABI measurements. Associations of PAD/PCA with new ischemic stroke events and all cause mortality were analyzed. Hazard ratios (HR) were calculated using multivariable Cox proportional regression with 95% confidence intervals.

RESULTS

A total of 39,834 unique patients were included with a median follow up duration of 4.59 years. All abnormal ABI groups, except borderline PAD, were associated with increased risk of incident ischemic stroke after multivariate regression compared to normal ABI. A severity-dependent association was observed between PAD and ischemic stroke with moderate (HR, 1.22 [95% CI, 1.10-1.35]) and severe (HR, 1.19 [95% CI, 1.02-1.40]) categories conferring similar risk in comparison to normal ABI. Patients with PCA carried the greatest ischemic stroke risk (HR, 1.30 [95% CI, 1.15-1.46]). Similarly, abnormal ABI groups were associated with a significant risk for all cause mortality in a severity-dependent manner, with severe PAD conferring the greatest risk (HR, 3.07 [95% CI, 2.88-3.27]).

CONCLUSIONS

This study adds to the growing body of evidence that both PAD and PCA are independent risk factors for incident ischemic stroke and all cause mortality. The association of PAD severity and PCA with risk of ischemic stroke may help clinicians with risk stratification and determining treatment intensity.

Discordant Values in Lower Extremity Physiologic Studies Predict Increased Cardiovascular Risk

Background

Ankle‐brachial indexes (ABI) are a noninvasive diagnostic tool for peripheral arterial disease and a marker of increased cardiovascular risk. ABI is calculated using the highest systolic blood pressure of the 4 ankle arteries (bilateral dorsalis pedis and posterior tibial). Accordingly, patients may be assigned a normal ABI when the result would be abnormal if calculated using one of the other blood pressure readings. Cardiovascular outcomes for patients with discordant ABIs are undescribed.

Methods and Results

We performed a retrospective study of patients who underwent ABI measurement for any indication between January 1996 and June 2018. Those with normal ABIs (1.00–1.39) were included. We compared patients with all 4 normal ABIs (calculated using all 4 ankle arteries; n=15 577, median age 64.0 years, 54.4% men) to those with discordant ABIs (at least 1 abnormal ABI ≤0.99; n=2095, median age 66.0 years, 47.8% men). The outcomes assessed were ischemic stroke, myocardial infarction, and all‐cause mortality. Compared with patients with concordant normal ABIs, patients with discordant ABIs were older; women; smoked; and had chronic kidney disease, coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease, hypertension, or prior stroke. Patients with discordant ABIs had a greater risk of myocardial infarction (hazard ratio [HR], 1.31; 95% CI, 1.10–1.56), ischemic stroke (HR, 1.53; 95% CI, 1.37–1.72), and all‐cause mortality (HR, 1.27; 95% CI, 1.16–1.39), including after adjustment for baseline comorbidities.

Conclusions

Discordant ABI results were associated with an increased risk of myocardial infarction, stroke, and all‐cause mortality in the studied population. Clinicians should examine ABI calculations using all 4 ankle arteries to better characterize a patient's cardiovascular risk.

Freeze artifact on full-field optical coherence tomography skin imaging

BACKGROUND/PURPOSE

Full-field optical coherence tomography (FFOCT) is an emerging imaging technique for rapid histological analysis. As FFOCT is introduced into the Mohs workflow, it is important to document the effect of tissue freezing on FFOCT images and any effect FFOCT has on frozen sections. Our study aimed to evaluate the changes on FFOCT images after tissue freezing as well as FFOCT imaging effects on frozen sectioning.

METHODS

Six normal skin specimens were imaged using FFOCT and subsequently frozen using a cryostat. The specimens were then reimaged using FFOCT and compared for any differences. To evaluate the effect of FFOCT imaging on frozen sections, five normal skin specimens were bisected and one half was imaged using FFOCT. Both halves underwent frozen sectioning and analysis.

RESULTS

Significant changes in the fat, sebaceous glands, eccrine glands, and dermal collage and minimal changes in the epidermis were seen after freezing. No effect on frozen sectioning was seen after FFOCT imaging.

CONCLUSION

As FFOCT is studied for use in Mohs, clinicians should be aware that freezing prior to imaging introduces significant artifact in the FFOCT image. If possible, specimens should undergo imaging prior to being frozen.

Recommendations for Solid Organ Transplantation for Transplant Candidates With a Pretransplant Diagnosis of Cutaneous Squamous Cell Carcinoma, Merkel Cell Carcinoma and Melanoma: A Consensus Opinion From the International Transplant Skin Cancer Collaborative (ITSCC)

Advancements in solid organ transplantation successfully extend the lives of thousands of patients annually. The tenet of organ stewardship aims to prevent the futile expenditure of scarce donor organs in patient populations with high mortality risk, to the detriment of potential recipients with greater predicted life expectancy. The development of skin cancer posttransplantation portends tremendous morbidity, adversely affecting quality of life for many transplant recipients. This special article, provided by of members of the International Transplant Skin Cancer Collaborative (ITSCC), will provide the transplant professional with a consensus opinion and recommendations as to an appropriate wait period pretransplantation for transplant candidates with a history of either cutaneous squamous cell carcinoma, malignant melanoma, or Merkel cell carcinoma.

[Hydatid disease of the first rib treated surgically by the Roos approach]

Hydatid disease is a parasitic infection due to Echinococcus granulosus. Since involvement of the ribs and in particular the first rib is rare, diagnosis and treatment in these locations can pose special problems. The purpose of this report is to describe the case of a 27-year-old man in whom an apical left opacity was discovered by chance. Clinical examination was normal. Thoracic ultrasound demonstrated multilocular cyst in the left apical region of the thorax. Thoracic computed tomography (CT) demonstrated a hydatid cyst originating from the first rib. The patient was operated using the technique known as the Roos approach. The procedure consisted of cystectomy with resection of the first rib. The multiloculated appearance of the lesion and erosion at the first rib was consistent with hydatid cyst. The Roos approach is the technique of choice for the treatment of the first rib.

[Mediastinal localisation of a thoracic duct lymphocele--account of a surgical case]

INTRODUCTION

Lymphocele of the thoracic duct is a rare pathological entity occurring as a consequence of deterioration and cystic dilation wall of this vessel. It may be of congenital or degenerative origin.

OBSERVATION

We report the case of a 47 year old patient, operated on for a symptomatic cyst localised by CT scan to the inferoposterior mediastinum. At postero-lateral thoracotomy it was identified as a lymphocele and completely resected. Chemical analysis of the liquid and histopathology study of the cystic wall confirmed the diagnosis. The patient's post operative course was uneventful.

CONCLUSION

This case demonstrates the clinical characteristics of this entity and describes diagnostic techniques and surgical management.

Tumeur myofibroblastique pulmonaire : intérêt de la chirurgie première

INTRODUCTION

Myofibroblastic tumours or pulmonary pseudotumours are rare and, though benign, they may become invasive and recur after excision.

CASE REPORT

We report the case of a child aged 14, presenting with mild haemoptysis, who had a solitary nodule at the base of the left lung. CT scanning suggested a hypervascular tumour. Fibreoptic bronchoscopy was normal and it was not possible to perform percutaneous biopsy on account of its proximal situation. A lobectomy was performed via a postero-lateral thoracotomy with a successful outcome. Histological examination revealed a myofibroblastic tumour.

CONCLUSION

Recourse to primary surgery is essential to confirm the diagnosis of a myofibroblastic pulmonary tumour. Complete resection is the only guarantee to prevent recurrence.

Liver retransplantation: a single-center outcome and financial analysis

Retransplantation of the liver (re-OLTx) accounts for approximately 10% of all liver transplants in the United States. The decision to offer a patient a second liver transplant has significant financial, ethical, and outcome implications. This large, single-center experience describes some outcome and financial data to consider when making this decision. One thousand three liver transplants were performed in 921 patients at our center. Patients were divided into adult and pediatric groups, and further by whether they received a single transplant or more than one. Overall survival, variation in survival by timing of re-OLTx, and survival in adults with hepatitis C were investigated, as were hospital charges and cost of re-OLTx. Adults, but not children, had a significant decrement in survival following a second transplant. Second transplants more than double the cost of the initial transplant, but there is a significantly higher cost associated with early retransplantation compared to the cost associated with late retransplantation (costs of first and second transplants included in both cases). This difference is due to a longer length of stay and associated cost in the ICU. Adult patients retransplanted early have the same overall survival compared to those done late. The sample size of the adult HCV re-OLTx population was too small to reach statistical significance despite their observed poorer outcome.

Two cases from the spectrum of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis is a poorly understood disease that mimics alcoholic liver disease histologically. Its natural history is not well defined, although gradual progression to cirrhosis has been described. Most patients with this condition have been obese, with or without associated diabetes or hyperlipidemia. No known effective treatment exists for nonalcoholic steatohepatitis, although weight loss may have a beneficial effect. We report two cases of nonalcoholic steatohepatitis. One patient with well-established nonalcoholic steatohepatitis had cirrhosis with a complete loss of fat on subsequent liver biopsy despite a gain in weight, simulating cryptogenic cirrhosis. In another patient, the condition improved after use of ursodeoxycholic acid; this agent may be a potential therapeutic agent for the treatment of nonalcoholic steatohepatitis. We believe these two cases represent the spectrum of this condition: on the one end is a progressive liver disease that in some instances may be a cause of cryptogenic cirrhosis; at the other end, a potentially treatable liver condition.