A 68-Year-Old Woman Who Has Sustained a Hip Fracture and Requires Urgent Surgery

Author:
Ronald N. Rubin, MD—Series Editor

Citation:
Rubin RN. A 68-year-old woman who has sustained a hip fracture and requires urgent surgery. Consultant. 2017;57(3):178-179.

A 68-year-old woman was shopping with her daughter when she tripped on a curb and fell, breaking her hip. The ambulance personnel confirmed her right leg to be shortened and laterally rotated, and they transported her to the hospital where an acute intertrochanteric fracture was confirmed. The orthopedics service wished to perform surgery in the next day or two but wanted to perform appropriate preoperative evaluation prior to doing so.

More complete evaluation revealed that the woman had experienced no dizziness or syncope with the fall. She had osteoporosis, diagnosed by way of bone density evaluation, and had been taking calcium and vitamin D supplementation. She reported that her health was otherwise good, with no acute events or hospitalizations in recent years. There was no history of overt congestive heart failure (CHF) or coronary artery disease (CAD), and she was able to ascend at least one flight of stairs without dyspnea or chest pain.

She had had type 2 diabetes mellitus for a decade, which had been managed with an insulin regimen, and she had a recent hemoglobin A_1C level of 6%. Kidney disease had developed in the past 3 years, attributed to her diabetes, with a recent creatinine level of 2.4 mg/dL.

Preoperative laboratory test results included normal complete blood cell count results. The results of a comprehensive metabolic panel included a random blood glucose level of 130 mg/dL, a blood urea nitrogen level of 34 mg/dL, a creatinine level of 2.6 mg/dL, and otherwise normal values.

Electrocardiography revealed nonspecific ST-T segment changes but was otherwise normal. An echocardiogram showed an ejection fraction of 50%.

Answer and discussion on next page.

Answer: C, her age and sex are not associated with increased surgical risk

The old and cynical saying, “The operation was a success, but the patient died,” unfortunately has a relationship to the truth. Even in 2017, there is a finite and, in some situations, significant risk for operative and/or perioperative (ie, within 30 days of induction of anesthesia) complications or mortality.¹ The most dangerous risks are for cardiac complications—CHF, myocardial infarction, and cardiac arrest. And, in patients who sustain such complications, the mortality rate is at least 33%.¹ Therefore, any diagnostic and/or therapeutic strategies to enable the preemptive diagnosis and treatment of such complications are important in making major noncardiac surgery safer for the large population of patients requiring it, the number of whom will only grow larger as the US population ages.

There is a good body of literature to guide us in these situations. The diagnostic and therapeutic trials usually divide major noncardiac surgery patients’ time interval into preoperative and perioperative phases. The vignette presented here addresses the preoperative aspects of risk assessment.

Assessing Cardiac Risk of Surgery

As is usual and useful with the availability of large amounts of patient data these days, a variety of well-validated risk index schemes have been developed in which to place a given patient’s clinical variables and generate a risk assessment.¹ Two frequently used models are the Revised Cardiac Risk Index (RCRI),^2,3 which evaluated 4315 patients, and the American College of Surgeons National Surgery Quality Improvement Program Surgical Risk Calculator,⁴ which evaluated the amazing number of 1,414,006 patients.The RCRI is more simple and practical, while the Surgical Risk Calculator is superior in predictive value but harder to use.

The developers of both tools utilized a variety of preoperative clinical data, statistically evaluated which items were truly independent risk factors, and then were able to generate a finite estimate of risk for complications.^2-4 The list of patient characteristics of significance in the RCRI was found to include the following: age older than 75 years; male sex; preexisting chronic renal insufficiency (ie, preoperative serum creatinine level > 2.0 mg/dL); CAD; CHF; diabetes requiring insulin; a history of recent acute or serious medical conditions such as stroke or stent placement; and acute trauma such as hip fracture. Each of these characteristics was assigned a risk point of 1.0 in the RCRI. Patients with 0 points had a 0.5% rate of major perioperative cardiac complication; with 1 point, the rate was 1.3%; with 2 points, the rate was 3.6%; and with 3 points, the rate was a formidable 9.1%.²

These tools serve as a valuable, convenient method to estimate cardiac surgical risk. With the advent of more refined tests, other studies performed prior to surgery have been evaluated in attempts to more accurately define operative risk. Preoperative cardiac stress testing has been evaluated, especially for patients of limited functional capacity, which might impair the accuracy of the risk models. The data supporting the use of thallium 201 exercise stress testing⁵ and even preoperative coronary computed tomography scanning⁶ are, in this author’s opinion, lukewarm at best, with an essentially equivalent number of cases of risk underestimation and risk overestimation using a risk index as baseline.¹ A more convenient, easy, and less expensive method involves preoperative cardiac biomarker measurements. Data to date are quite promising, with natriuretic peptide measurements improving the accuracy of predicting adverse events and reclassifying risk index profiles in 15% of patients, but on both sides of the issue, that is demonstrating more risk in some cases and downgrading to less risk in others.⁷

Returning to the presented case, our patient demonstrated 3 literature-documented clinical risk factors—a creatinine level greater than 2.0 mg/dL (Answer A), a serious recent traumatic event (a hip fracture, which was the reason for her need for surgery, Answer B), and the presence of diabetes requiring insulin (Answer D). Thus, these 3 answers are incorrect. Although natriuretic peptide levels had not yet been measured in our patient, elevation has been found to be associated with increased perioperative risk, and thus Answer E also is incorrect. The patient’s age and sex are not part of literature-based risk indexes—male sex and age above 75 years are—and therefore, Answer C is the correct answer here.

Patient Follow-Up

In light of our patient’s cardiac index evaluation indicating a theoretically significant risk value of 9% or more for cardiovascular complication, she underwent preoperative thallium 201 exercise stress testing, the findings of which were negative for cardiac ischemia, and underwent natriuretic peptide measurements, the results of which were normal. She proceeded to surgery and tolerated the procedure without event, either acutely or throughout the 30-day postoperative period.

Take-Home Message

Many diagnostic and therapeutic maneuvers have been evaluated for reducing serious complications and death in the perioperative period for patients undergoing major noncardiac surgery. Routing use of β-blockers and/or α₂-adrenergic agonists, liberal blood transfusions, and aspirin as primary prevention of stroke and AMI have been disappointing. Monitoring for asymptomatic myocardial ischemia, AMI, and other morbid events has revealed a strong association between increased troponin levels and the risk for these poor outcomes. Hopefully, this observation will lead to the more appropriate application of diagnostic and therapeutic interventions to lower the risk of poor outcomes in this group of patients.

Ronald N. Rubin, MD, is a professor of medicine at the Lewis Katz School of Medicine at Temple University and is chief of clinical hematology in the Department of Medicine at Temple University Hospital in Philadelphia, Pennsylvania.

References:

1. Devereaux PJ, Sessler DI. Cardiac complications in patients undergoing major noncardiac surgery. N Engl J Med. 2015;373(23):2258-2269.
2. Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100(10):1043-1049.
3. Ford MK, Beattie WS, Wijeysundera DN. Systemic review: prediction of perioperative cardiac complications and mortality by the Revised Cardiac Risk Index. Ann Intern Med. 2010;152(1):26-35.
4. Bilimoria KY, Liu Y, Paruch JL, et al. Development and evaluation of the universal ACS NSQIP surgical risk calculator: a decision aid and informed consent tool for patients and surgeons. J Am Coll Surg. 2013;217(5):833-842.e3.
5. Eagle KA, Coley CM, Newell JB, et al. Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery. Ann Intern Med. 1989;110(11):859-866.
6. Sheth T, Chan M, Butler C, et al; Coronary Computed Tomographic Angiography and Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (Coronary CTA VISION) Study Investigators. Prognostic capabilities of coronary computed tomographic angiography before non-cardiac surgery: prospective cohort study. BMJ. 2015;350:h1907.
7. Rodseth RN, Biccard BM, Le Menach Y, et al. The prognostic value of pre-operative and post-operative B-type natriuretic peptides in patients undergoing noncardiac surgery: B-type natriuretic peptide and N-terminal fragment of pro-B-type natriuretic peptide: a systematic review and individual patient data meta-analysis. J Am Coll Cardiol. 2014;63(2):170-180.