Does Preoperative Hemoglobin Value Predict Does Preoperative Hemoglobin Value Predict Postoperative Cardiovascular Complications Postoperative Cardiovascular Complications

after Total Joint Arthroplasty?after Total Joint Arthroplasty?

Kishor Gandhi MD, MPH, Eugene Viscusi MD, Kishor Gandhi MD, MPH, Eugene Viscusi MD, Luis Pulido MD, and Javad Parvizi, MDLuis Pulido MD, and Javad Parvizi, MD

Introduction:Introduction: Anemia defined by the World Health Organization (WHO)Anemia defined by the World Health Organization (WHO)11::

Hemoglobin (Hb) <12 g/dl in womenHemoglobin (Hb) <12 g/dl in women Hemoglobin (Hb) <13 g/dl in menHemoglobin (Hb) <13 g/dl in men

The incidence of anemia in the U.S. age>70 is approximately 13%The incidence of anemia in the U.S. age>70 is approximately 13%22..

Literature shows:Literature shows:

Mild degrees of anemia or polycythemia increased risk of 30-day mortality Mild degrees of anemia or polycythemia increased risk of 30-day mortality and cardiac events in older male veterans undergoing non-cardiac and cardiac events in older male veterans undergoing non-cardiac surgeriessurgeries33. .

Multicenter Cohort study found preoperative anemia to be independently Multicenter Cohort study found preoperative anemia to be independently associated with adverse outcomes (death, stroke, or acute kidney injury) associated with adverse outcomes (death, stroke, or acute kidney injury) after cardiac surgeryafter cardiac surgery44..

Preoperative anemia may have independent harmful effects due to limited Preoperative anemia may have independent harmful effects due to limited patient physiologic reserve and added stress of surgery.patient physiologic reserve and added stress of surgery.

1. WHO. Technical Report Series No. 405, Geneva, Switzerland: WHO.1968.1. WHO. Technical Report Series No. 405, Geneva, Switzerland: WHO.1968.2. Penninx et al. Journal of Gerontology. 2006. Vol. 61A. 474-479.2. Penninx et al. Journal of Gerontology. 2006. Vol. 61A. 474-479.3. Wu et al. JAMA. 2007; 297: 2481-2488. 3. Wu et al. JAMA. 2007; 297: 2481-2488. 4. Karkouti et al. Circulation 2008;117;478-484. 4. Karkouti et al. Circulation 2008;117;478-484.

Introduction (cont’d):Introduction (cont’d):

Limited information is available on the impact of preoperative anemia in the Limited information is available on the impact of preoperative anemia in the elderly population following Total Joint Arthroplasty (TJA).elderly population following Total Joint Arthroplasty (TJA).

Total joint replacements are increasing steadily each year to an estimated Total joint replacements are increasing steadily each year to an estimated 3.48 million primary knee and 572,000 primary hip replacements by the year 3.48 million primary knee and 572,000 primary hip replacements by the year 2030. 2030. Epidemiologic implications are significant.Epidemiologic implications are significant.

OObjectivebjective::

Examine the association between preoperative hemoglobin levels and Examine the association between preoperative hemoglobin levels and cardiovascular complications in patients undergoing total hip and knee cardiovascular complications in patients undergoing total hip and knee replacements.replacements.

Methods:Methods: Following IRB approval of this retrospective study the sample (n=3954) consisted Following IRB approval of this retrospective study the sample (n=3954) consisted

of all patients who underwent primary hip and knee arthroplasty during the years of all patients who underwent primary hip and knee arthroplasty during the years 2004 and 2005.  2004 and 2005.  

Patients were followed postoperatively during their hospitalization and were Patients were followed postoperatively during their hospitalization and were observed for complications. observed for complications.

The past medical history of all patients was extracted from the preoperative The past medical history of all patients was extracted from the preoperative evaluation office records and linked to the database containing patient information evaluation office records and linked to the database containing patient information on complications.on complications.

AnalysisAnalysis All statistical analysis was conducted with use of SPSS software (version 11.0, All statistical analysis was conducted with use of SPSS software (version 11.0,

Chicago, Illinois).Chicago, Illinois).

Bivariate analysesBivariate analyses were conducted on the three comparison groups categorized by were conducted on the three comparison groups categorized by preoperative hemoglobin values: preoperative hemoglobin values: 1. Less than 12 g/dl (anemia group) 1. Less than 12 g/dl (anemia group) 2. 12-14 g/dl (normal reference group)2. 12-14 g/dl (normal reference group)3. Greater than 14 g/dl (above normal group)3. Greater than 14 g/dl (above normal group)

Primary outcomesPrimary outcomes measured were the occurrence of any postoperative measured were the occurrence of any postoperative cardiovascular complications:cardiovascular complications:

Angina, arrhythmias, bradycardia, asystole, CHF, myocardial Infarctions, Angina, arrhythmias, bradycardia, asystole, CHF, myocardial Infarctions, compartment syndrome, DVT’s, hypertension, hypotension, hypovolemic compartment syndrome, DVT’s, hypertension, hypotension, hypovolemic shock, and vascular injuriesshock, and vascular injuries

  Multivariate analysesMultivariate analyses controlled for potential confounders including: controlled for potential confounders including:Age, BMI, race, gender, O.R. time, joint type (hips vs. knees), number of Age, BMI, race, gender, O.R. time, joint type (hips vs. knees), number of

joints joints (unilateral vs. bilateral), DM, HTN, cardiac history (CAD, arrhythmia, CHF, (unilateral vs. bilateral), DM, HTN, cardiac history (CAD, arrhythmia, CHF, valvular disorder), PVD, DVT, and previous placement of Greenfield filter.valvular disorder), PVD, DVT, and previous placement of Greenfield filter.

Results:Results:Table 1-Patient Demographics (n=3954)Table 1-Patient Demographics (n=3954)

Results:Results: Table 2: Bivariate analysis of cardiovascular Table 2: Bivariate analysis of cardiovascular complications among groups (Total Sample Size=3954)complications among groups (Total Sample Size=3954)

Cardiac complication include: Angina, Tachycardia (SVT’s), Arrhythmias (A-fib), Cardiac complication include: Angina, Tachycardia (SVT’s), Arrhythmias (A-fib), bradycardia, Asystole, CHF, and Myocardial Infarction.bradycardia, Asystole, CHF, and Myocardial Infarction.

Vascular complications include: Compartment syndrome, DVT’s, Hypertension, Vascular complications include: Compartment syndrome, DVT’s, Hypertension, Hypotension, Hypovolemic shock, and Vascular injury.Hypotension, Hypovolemic shock, and Vascular injury.

ComplicationsComplications Hgb:<12Hgb:<12

(n=742)(n=742)

Hgb:12-14Hgb:12-14

(n=1914)(n=1914)

Hgb:>14Hgb:>14

(n=1298)(n=1298)

P valueP value

Cardiovascular Cardiovascular (n=116)(n=116)

41 (5.5%)41 (5.5%) 47 (2.5%)47 (2.5%) 28 (2.2%)28 (2.2%) P<0.05P<0.05

Results:Results:Table 3: Logistic Regression Model for Cardiovascular Table 3: Logistic Regression Model for Cardiovascular ComplicationsComplications

Variables in the Equation

.575 .251 5.234 1 .022 1.778

.024 .274 .008 1 .931 1.024

.040 .011 14.104 1 .000 1.041

.012 .009 1.860 1 .173 1.012

.306 .319 .921 1 .337 1.358

-.423 .330 1.646 1 .199 .655

.096 .236 .165 1 .685 1.101

.004 .002 2.730 1 .098 1.004

-.061 .356 .029 1 .865 .941

.395 .224 3.107 1 .078 1.485

.431 .327 1.731 1 .188 1.538

.347 .261 1.763 1 .184 1.415

.610 .471 1.677 1 .195 1.841

-.397 .432 .842 1 .359 .673

.021 .290 .005 1 .941 1.022

.279 .232 1.448 1 .229 1.322

-.367 .270 1.851 1 .174 .693

-.027 .750 .001 1 .971 .973

-1.740 1.152 2.282 1 .131 .175

1.886 1.317 2.049 1 .152 6.590

-7.637 .910 70.449 1 .000 .000

Hgb<12

Hgb>14

age

bmi

Black

other_race

male

or_time

side_recode

knees

card_arr

card_cad

card_chf

card_val

dm

htn

lipids

pvd

dvt

greenfie

Constant

Step1

a

B S.E. Wald df Significance Odds Ratio

Variable(s) entered on step 1: Hgb12, Hgb14, age, bmi, Black, other_race, male, or_time,side_recode, knees, card_arr, card_cad, card_chf, card_val, dm, htn, lipids, pvd, dvt, greenfie.

a.

Results:Results:Table 4: Logistic Regression Model SummaryTable 4: Logistic Regression Model Summary

HemoglobinHemoglobin BetaBeta S.E.S.E. P valueP value Odds RatioOdds Ratio

Hgb<12Hgb<12 0.5750.575 0.2190.219 0.0220.022 1.7781.778

Hgb 12-14Hgb 12-14 ReferenceReference ReferenceReference ReferenceReference ReferenceReference

Hgb> 14Hgb> 14 0.0240.024 0.2740.274 0.9310.931 1.0241.024

Discussion:Discussion:    In this analysis, 742 patients had preoperative anemia, 1914 patients with hemoglobin levels in the In this analysis, 742 patients had preoperative anemia, 1914 patients with hemoglobin levels in the

reference range, and 1298 patients in the above normal group (Table 1). reference range, and 1298 patients in the above normal group (Table 1).

      Average age of patients were 65.9 (Hgb<12), 65.5 (reference group), and 60.7 years (Hgb>14). Average age of patients were 65.9 (Hgb<12), 65.5 (reference group), and 60.7 years (Hgb>14).       The anemia group had longer average length of surgery (128.3 minutes), compared to the The anemia group had longer average length of surgery (128.3 minutes), compared to the

reference and above normal groups (114.3 and 116.1 minutes, respectively).reference and above normal groups (114.3 and 116.1 minutes, respectively).      A higher percentage of patients with preoperative anemia had a history of CAD (16.8%), CHF A higher percentage of patients with preoperative anemia had a history of CAD (16.8%), CHF

(3.6%), arrhythmias (7%), and valvular disorders (11%). (3.6%), arrhythmias (7%), and valvular disorders (11%).     IIncreased occurrence of comorbid hypertension (59.6%), diabetes (3.6%), peripheral vascular ncreased occurrence of comorbid hypertension (59.6%), diabetes (3.6%), peripheral vascular

disease (1.7%), and DVT’s (3.6%) were also noted in this group. disease (1.7%), and DVT’s (3.6%) were also noted in this group.     Bivariate analyses indicated that patients with preoperative anemia have greater cardiovascular Bivariate analyses indicated that patients with preoperative anemia have greater cardiovascular

complications (Table 2). complications (Table 2).

    Due to significant differences in potential confounders between the three groups’ bivariate analyses, Due to significant differences in potential confounders between the three groups’ bivariate analyses, they were controlled for in logistic regression models (Table 3). they were controlled for in logistic regression models (Table 3).

    Logistic regression model showed that patients with preoperative anemia (Hgb<12) have Logistic regression model showed that patients with preoperative anemia (Hgb<12) have statistically significant risk of cardiovascular complications (Odds Ratio=1.778, p<0.05). statistically significant risk of cardiovascular complications (Odds Ratio=1.778, p<0.05).

Conclusion:Conclusion:      In this retrospective analysis, anemic patients (those identified with In this retrospective analysis, anemic patients (those identified with

lower preoperative hemoglobin values) have an increased risk of lower preoperative hemoglobin values) have an increased risk of cardiovascular complications. cardiovascular complications.

      Preoperative hemoglobin levels may be predictive of postoperative Preoperative hemoglobin levels may be predictive of postoperative

cardiovascular complications. cardiovascular complications.       These patients may benefit from more than just reversal of anemia These patients may benefit from more than just reversal of anemia

preoperatively, rather increased surveillance for postoperative preoperatively, rather increased surveillance for postoperative complications. complications.

    

Limitations and Implications:Limitations and Implications: Limitations of our study include:Limitations of our study include:

Small sample size relative to other published studies (JAMA).Small sample size relative to other published studies (JAMA). Retrospective analyses may result in omission of information Retrospective analyses may result in omission of information

regarding co-morbidities experienced by patients.regarding co-morbidities experienced by patients. There is the potential for selection bias because highest risk There is the potential for selection bias because highest risk

patients may not qualify for TJA. patients may not qualify for TJA. Information of intraoperative transfusion was not in the database Information of intraoperative transfusion was not in the database

and was not considered in the analysis.and was not considered in the analysis.

Implications:Implications: Patients identified to be at higher risk of cardiovascular risk may benefit Patients identified to be at higher risk of cardiovascular risk may benefit

from additional surveillance postoperatively. from additional surveillance postoperatively.