MILITARY MEDICINE, 173, 2:193, 2008 Crdiovsculr Disese in Forwrd Militry Hospitl during Opertion Irqi Freedom: A Report from Deployed Crdiologists MAJ Lnce Sullenberger, MC USA*; MAJ Philip J. Gentlesk, MC USA ABSTRACT Bckground: No published dt re vilble regrding crdic evlutions in forwrd militry hospitl setting. Methods: Two crdiologists deployed in support of Opertion Irqi Freedom identified ll of their crdic evlutions. Ptient demogrphic dt, evlutions performed, outcomes, nd return-to-duty rtes were determined. Results: Four hundred sixty-nine predominntly mle ptients were evluted, with men ge of 39 10 yers. The most common resons for referrl were ischemic evlution (n 283), rrhythmi/plpittions (n 83), nd syncope (n 57). Of those referred with ischemi, the men Frminghm 10-yer event risk clculted ws low t 5.3 3.1%; 86% of militry ptient evlutions reveled no identifible crdiovsculr pthologicl condition, nd ptients were returned to duty. Conclusions: Crdiology support, with the vilbility of echocrdiogrphy nd stress testing in the theter of opertions, ws ble to provide crdiovsculr consulttive evlutions nd mngement nd to reduce rtes of medicl evcutions out of the theter of opertions. INTRODUCTION Opertion Irqi Freedom is n ongoing militry opertion involving 135,000 troops deployed from the United Sttes to Irq t ny one time. 1 In ddition to providing medicl cre for deployed troops, militry medicl personnel lso tret colition forces, nd they provide cre to civilin (U.S. nd other) contrctors nd militry detinees. By convention, wrtime ptient cre is ctegorized s originting from combt-relted trum, noncombt-relted trum, or medicl disese. 2 Historiclly, infectious diseses were the gretest medicl thret to militry personnel in combt opertions. 3 With dvnces in ntimicrobil therpy nd snittion, however, crdiovsculr disese hs overtken infectious diseses s the most likely cuse for medicl dmission to combt support hospitl.. 4 Despite the number of crdiovsculr disese complints mong soldiers, there re no dt vilble on crdiovsculr evlutions performed in combt theter. We sought to describe the referrls to intrtheter crdiology consultnts during Opertion Irqi Freedom. METHODS From December 2004 through November 2005, the uthors, both bord-certified U.S. Army crdiologists, were deployed in consecutive 6-month rottions with the combt support hospitl locted in north-centrl Irq, in support of Opertion Irqi Freedom. The 44th Medicl Commnd, which dmin- *Crdiology Service, Wlter Reed Army Medicl Center, Wshington, DC 20307. Crdiology Service, Brooke Army Medicl Center, Fort Sm Houston, TX 78234. The opinions nd ssertions herein re the privte views of the uthors nd re not to be construed s reflecting the views of the U.S. Deprtment of the Army or the U.S. Deprtment of Defense. This mnuscript ws received for review in April 2007. The revised mnuscript ws ccepted for publiction in November 2007. istrtively supervised the support hospitls, designted ech uthor s crdiology consultnt for his respective tour of duty. Ech uthor received referrls from deployed providers throughout the Irqi theter. Using vilble ssets, the uthors performed ptient evlutions, undertook necessry testing, nd implemented indicted tretments. Moreover, the crdiology consultnt decided whether referred ptients could return to their duty sttions. If ptient needed further evlution or tretment beyond our cpbilities, then the ptient ws trnsferred to higher level of medicl cre when vilble. U.S. ptients were evcuted to U.S. militry tertiry cre medicl center in Germny or the United Sttes. Foreign ntionls were evcuted or trnsferred to medicl centers in their country of origin. Eligible ptients included U.S. militry personnel nd civilins nd foreign ntionls. Ptient dt were collected prospectively from ptient chrts nd included ge, militry sttus, indiction for referrl, dignostic evlution, outcomes of tests performed, nd decisions regrding return to duty or evcution. We prospectively identified crdic risk fctors nd recorded Frminghm risk scores for 10-yer risk in ptients referred for crdiovsculr cre. 5 Trnsthorcic nd trnsesophgel echocrdiogrphy ws performed by using n Acuson Cypress echocrdiogrphy system (Siemens Medicl, Mlvern, Pennsylvni). Exercise stress testing ws performed by using Series 2000 tredmill system (GE Helthcre, Wukesh, Wisconsin). All stress tests were performed by using the Bruce protocol, under the direct supervision of the crdiology consultnt. Exercise or dobutmine stress echocrdiogrphy ws performed by using n Acuson Cypress echocrdiogrphy system for imge cquisition nd review. Dt on the referrl popultion were evluted to determine the most frequent indictions for referrl to the crdiovsculr consultnt nd ptient demogrphic chrcteristics. MILITARY MEDICINE, Vol. 173, Februry 2008 193
The ptients were ctegorized with respect to whether they hd possible or definite cute coronry syndrome. Return-toduty rtes fter in-theter evlution were lso determined for militry ptients. Results re expressed s men SD where pproprite. Ctegoricl vribles were compred by using 2 nlysis or two-sided Fisher s exct test (for cell size of 5). Sttisticl nlyses were performed by using the SPSS 11.5 softwre progrm (SPSS, Chicgo, Illinois), nd sttisticl significnce ws defined s two-sided p vlue of 0.05. RESULTS Four hundred sixty-nine predominntly mle ptients, with men ge of 39 10 yers, were referred for crdiovsculr consulttion during the study period (Tble I). The most common referrl complints were chest pin or dyspne on exertion (n 283; 60.3%), plpittion or rrhythmi (n 83; 17.7%), nd syncope (n 57; 12.2%) (Tble II). Of the 469 ptients referred, 386 (82.3%) underwent dvnced dignostic procedures. Procedures performed included 201 trnsthorcic echocrdiogrms, 15 trnsesophgel echocrdiogrms, 95 exercise stress tests, nd 213 exercise stress tests with echocrdiogrphy (Tble III). Thirteen percent of ptients hd bnorml stress evlution results.. Trnsthorcic echocrdiogrms yielded bnorml results for 29% of the ptients. Of the referrls for ischemic evlution, 19.4% were identified s hving n bnormlity (Tble IV). A ST-elevtion myocrdil infrction requiring thrombolytic therpy ws identified in 3 ptients (1.5%) referred for ischemic evlution. There were two sudden crdic deths, both of which occurred in civilin ptients. Overll, the rte of identified bnormlities in U.S. militry personnel ws 15.6%, significntly lower thn the 31.9% in non-u.s. militry ptients (p 0.05). Mediction use within the combt theter of opertions ws similr to tht in community prctice (Tble V). In TABLE I. Demogrphic Findings for the 469 Ptients Seen for Crdiology Complints by Crdiology Consultnts during Opertion Irqi Freedom III Number Percent Totl ptients 469 100 U.S. militry 379 80.8 Active duty 125 33 Reserve 77 20.3 Gurd 176 46.4 Irqi militry 6 1.3 Civilin 84 17.9 U.S. 44 52.4 Irqi 9 10.7 Other 31 36.9 Mle 421 89.9 Age (yers) 38.8 10.4 TABLE II. Distribution of Referrl Complints Complint No. Percent Chest pin or ischemic equivlent 283 60.3 Acute coronry syndrome 201 42.9 Plpittions 34 7 Arrhythmi 49 10.7 Brdyrrhythmi 5 1.1 SVT 13 2.8 Atril fibrilltion/flutter 10 2.1 Ventriculr b 21 4.5 Syncope/presyncope 57 12.2 Hert filure 7 1.5 Vlvulr hert disese 11 2.3 Crdiomyopthy 7 1.5 Chest trum 5 1.1 Hypertensive urgency/emergency c 3 0.6 Congenitl hert disese 5 1.1 Pericrditis 3 0.6 Echocrdiogrm during resuscittion 10 2.1 Elevted crdic risk fctors 19 4.1 SVT suprventriculr tchycrdi nd includes sinus tchycrdi, tril tchycrdi, junctionl tchycrdi, trioventriculr nodl reentrnt tchycrdi, trioventriculr reciprocting tchycrdi. b Ventriculr rrhythmi includes premture ventriculr contrctions, ventriculr tchycrdi, ventriculr fibrilltion. c Includes one cse of descending ortic dissection. TABLE III. Description of Procedures Performed on 469 Referrls to Crdiology during OIF3 Crdiology Evlutions (N 469) Norml Abnorml Procedure No. No. % No. % Trnsthorcic echocrdiogrm 201 142 70.6 59 29.3 Trnsesophgel echocrdiogrm 15 7 46.7 8 53.3 Exercise stress test 308 268 87.0 40 13.0 Exercise stress echocrdiogrm 213 179 84.0 34 16.0 The 308 exercise stress tests include the exercise dt from the 213 exercise stress echocrdiogrms. ptients referred for possible cute coronry syndrome, rtes of documented spirin, -drenergic receptor blocker, nd HMG-coenzyme A reductse therpy were 94.9%, 71.8%, nd 48.7%, respectively. For 110 ptients referred becuse of concern bout ischemic disese, we were ble to prospectively record the clculted Frminghm risk score. The men clculted 10-yer event risk ws 5.3 3.1% 6 (Fig. 1). The predominnt modifible crdic risk fctors in this popultion were hyperlipidemi (38%) nd use of tobcco products (36%). The distributions of crdic risk fctors re presented in Figures 2 nd 3. Eighty-six percent of U.S. militry ptients who received in-theter crdiology consulttion returned to duty without the need for evcution out of theter. Return-to-duty rtes were similr regrdless of the presenting complint nd were consistent with results for n overll lower-risk group of U.S. militry ptients evluted (Tble VI). 194 MILITARY MEDICINE, Vol. 173, Februry 2008
TABLE IV. Evlution of 201 Ptients Presenting with Definite or Possible Acute Coronry Syndrome All U.S. Militry Non-U.S. Militry Complint No. % No. % No. % p Acute coronry syndrome 201 100 154 76.6 47 23.4 Positive troponin 8 4 0 0 8 17 0.001 Non-ST elevtion MI b 5 2.5 0 0 5 10.6 0.001 ST elevtion MI b 3 1.5 0 0 3 6.4 0.003 Abnorml echocrdiogrm 16 8 10 6.5 6 12.8 0.391 Abnorml stress 24 11.9 16 10.4 8 17 0.009 Abnorml evlution c 39 19.4 24 15.6 15 31.9 0.017 Deth 2 1 0 0 2 4.3 0.052 Troponins were drwn in 114/201 ptients. b MI myocrdil infrction. c Abnorml evlution includes deth, positive troponin, bnorml stress testing, or bnorml echocrdiogrm. TABLE V. Use of Crdic Medictions in Ptients Referred for Possible Acute Coronry Syndrome with Abnorml Evlution All U.S. Militry Non-U.S. Militry Mediction No. % No. % No. % p -blocker 28 71.8 16 66.7 12 80 0.368 Aspirin 37 94.9 23 95.8 14 93.3 0.731 Thrombolytic 3 7.7 1 4.2 2 13.3 0.547 Sttin 19 48.7 9 37.5 10 67.1 0.076 Heprin 11 28.2 3 12.5 8 53.3 0.010 ACE-inhibitor 10 25.6 4 16.7 6 40 0.170 Clopidogrel 12 30.8 7 29.2 5 33.3 0.574 Includes low moleculr weight heprin. 10 yer event rte 7 6 5 4 3 2 1 0 Frminghm 10 yer risk 1 Chest pin Positive stress imging Coronry rtery disese FIGURE 1. Ten-yer Frminghm risk of developing nginl chest pin, suffering nonftl myocrdil infrction, or dying for 110 ptients referred with chest pin. The p vlues between those groups with chest pin nd those with positive stress imging or coronry rtery disese were not sttisticlly significnt (p 0.98, p 0.26). Percent of Ptients with Individul Risk Fctor 60% 40% 20% 0% Hypertension Hyperlipidemi Tobcco Fmily History Dibetes BMI>30 FIGURE 2. Percentges of ptients with individul crdic risk fctors. Hypertension ws defined s systolic blood pressure of 140 mm Hg or distolic blood pressure of 90 mm Hg; hyperlipidemi ws defined s low-density lipoprotein-cholesterol levels of 160 mg/dl or high-density lipoprotein cholesterol levels of 40 mg/dl. BMI, body mss index. Percent of Ptients Presenting with Multiple Crdic Risk Fctors 35% 30% 25% 20% 15% 10% 5% 0% 0 risk fctors 1 risk fctor 2 risk fctors 3 risk fctors 4 risk fctors 5 risk fctors FIGURE 3. Percentges of U.S. militry ptients referred with possible ischemic symptoms presenting with crdic risk fctors. Risk fctors included mle ge of 45 yers, femle ge of 55 yers, body mss index of 30 kg/m 2, systolic blood pressure of 140 mm Hg or distolic blood pressure of 90 mm Hg, low-density lipoprotein-cholesterol level of 160 mg/dl, high-density lipoprotein-cholesterol level of 40 mg/dl, use of smokble tobcco products, fmily history of erly coronry rtery disese (mle first-degree reltive with documented coronry disese before 55 yers of ge or femle first-degree reltive before 65 yers of ge), nd dibetes mellitus. Of the 269 ptients evluted between June nd November, 34 were evcuted out of Irq fter crdiovsculr consulttion. Of the 16 ptients evcuted becuse of concern bout ischemi, 11 were found to hve symptomtic obstructive coronry rtery disese necessitting dvnced medicl nd interventionl mngement (Tble VII). Crdiology con- MILITARY MEDICINE, Vol. 173, Februry 2008 195
TABLE VI. Return to Duty Rtes of Militry Personnel Referred to Crdiology Consultnts during Opertion Irqi Freedom III Complint No. Percent All crdic referrls 323 86.0 Chest pin/cute coronry syndrome 195 87.1 Syncope/presyncope 37 86.0 Arrhythmi/plpittions 67 88.2 Evlution for risk fctors 15 88.2 sulttion identified two ptients with severe vlvulr disese (severe ortic stenosis with syncope nd severe mitrl regurgittion identified on exmintion), who underwent definitive surgery. Three ptients were evcuted becuse of hert filure (one ech with hypertensive crdiomyopthy, restrictive crdiomyopthy, nd decompensted trnsposition of the gret vessels). Additionlly, one ptient ech ws evcuted becuse of identifiction of hypertrophic crdiomyopthy, myocrditis, nd symptomtic junctionl brdycrdi. DISCUSSION Militry opertions re dependent on their medicl ssets to mintin the strength nd helth of the unit. With the dvncement of medicl knowledge nd tretment cpbilities, the demogrphic fetures of diseses ffecting deployed soldiers hve lso chnged. Dt from pst conflicts revel tht the most common diseses leding to dmission to combt hospitl were infectious. 6 8 Recent dt from Opertion Irqi Freedom, however, revel tht crdiovsculr disese hs surpssed infectious diseses s the most frequent noncombt-relted reson for dmission. However, no dt exist on the chrcteristics of the crdiovsculr disese complints. The utiliztion of n in-theter crdiology consultnt for possible ischemic complints nd questions regrding the presence of cute coronry syndrome ws frequent reson for consulttion. The in-theter utiliztion of pproprite lbortory testing, echocrdiogrphy, nd tredmill testing llowed rte of identifiction of bnormlities similr to tht for ptients presenting to community emergency rooms with chest pin. 9,10 We were lso ble to evlute the risk fctor profile of ptients presenting with or referred becuse of ischemic symptoms. Frminghm risk scoring is vlidted method of estimting the risk of coronry disese over 10-yer period. 5 Our ptients hd Frminghm risks tht ctully fell into the low-risk profile, considered to be n event rte of 6%. Frminghm risk scoring does not include fmily history of premture coronry rtery disese in its prediction model, but fmily history of erly coronry disese remins cuse of concern for both ptients nd physicins. Thirty-six percent of our ptients reported fmily history of coronry rtery disese. Moreover, the verge number of crdic risk fctors per ptient ws two, which plces ptients in n intermediterisk ctegory. Our dt demonstrte the bility of in-theter crdiology consultnts to ssess crdiovsculr disese. We returned 86% of referred U.S. soldiers bck to their units fter they demonstrted norml crdiovsculr evlution results, without their leving the opertionl theter. This return-to-duty rte ws consistent mong ll types of mjor crdiovsculr complints. We treted mixed group of U.S. militry personnel, including ctive duty, reserve, nd Ntionl Gurd members. The ptient mixture ws dependent on vrible locl troop concentrtions nd referrl ptterns from outlying TABLE VII. Outcomes of 24 Ptients Air Evcuted from Irq by Crdiology Consultnt from June to December 2005 Reson for Air Evcution Unstble ngin in U.S. civilin contrctor with known coronry disese (1 ptient) Positive exercise stress echocrdiogrm (11 ptients) Indeterminte exercise stress echocrdiogrms (3 ptients) Vlvulr hert disese Severe ortic stenosis with syncope (1 ptient) Severe mitrl regurgittion (1 ptient) Congenitl hert disese Decompensted trnsposition of the gret vessels (1 ptient) Symptomtic junctionl brdycrdi (1 ptient) Arrhythmi Persistent sinus tchycrdi secondry to hyperthyroidism (1 ptient) Congestive hert filure New depressed LV systolic function (1 ptient) Restrictive crdiomyopthy (1 ptient) Plpittions nd bnorml electrocrdiogrm Found to hve hypertrophic crdiomyopthy (1 ptient) Myocrditis (1 ptient) Outcomes Percutneous coronry intervention 9 of 11 found to hve coronry lesion 50% of luminl dimeter. Medicl mngement-1; percutneous coronry intervention-6; coronry rtery bypss grfting, 2 None with obstructive coronry disese Aortic vlve replcement Mitrl vlve repir Pcemker plcement in U.S. in U.S. 196 MILITARY MEDICINE, Vol. 173, Februry 2008
medicl ssets. Therefore, we re unble to comment on differences in crdiovsculr disese prevlence between ctive duty nd reserve or Ntionl Gurd members. As with ny observtionl reporting, the dt re inherently bised. We certinly did not receive ll referrls. Ptients in combt theters my be evluted by multiple providers t differing loctions, with differing cpbilities, nd some ptients might hve been evcuted or returned to duty without in-theter crdiology consulttion. However, the vilbility of echocrdiogrphy nd tredmill testing during this period of observtion ws limited to our combt support hospitl. Also, the ptients with norml evlution results who were returned to duty fter their evlutions might hve been found lter to hve other medicl or psychologicl conditions. CONCLUSIONS Crdiovsculr symptoms nd complints re common mong U.S. soldiers nd support personnel in the modern er. The deployment of crdiologists during Opertion Irqi Freedom llowed thorough crdiovsculr exmintions to be performed within the wr theter. Most of the referred ptients were of low to intermedite risk, nd the vst mjority could be returned to duty fter evlution. Bsic history nd physicl exmintion skills, ugmented by 12-led electrocrdiogrphy, tredmill stress testing, exercise echocrdiogrphy, nd trnsthorcic echocrdiogrphy, were vluble ssets in the evlution of these ptients. REFERENCES 1. GloblSecurity.org: U.S. forces order of bttle: troop levels, Opertion Irqi Freedom. Avilble t http://www.globlsecurity.org/militry/ops/ irq orbt es.htm; ccessed August 20, 2006. 2. Defense Mnpower Dt Center: DoD personnel nd militry csulty sttistics. Avilble t http://sidpp.dmdc.osd.mil/personnel/ MMIDHOME.HTM; ccessed August 24, 2006. 3. Ognibene AJ, Brrett O (editors): Internl Medicine in Vietnm, Volume II: Generl Medicine nd Infectious Diseses. Wshington, DC, U.S. Government Printing Office, 1982. 4. Perkins J: Chnging wrs, chnging ptients: n exmintion of internl medicine prctice t combt support hospitl on the modern bttlefield. Presented t the Americn College of Physicins-Army Chpter Meeting, November 2005, Sn Antonio, TX. 5. Wilson PWF, D Agostino RB, Levy D, Belnger AM, Silbershtz H, Knnel WB: Prediction of coronry hert disese using risk fctor ctegories. Circultion 1998; 97: 1837 47. 6. Spurgeon N (editor): Vietnm Studies: Medicl Support of the U.S. Army in Vietnm, 1965 1970. Center for Militry History Publiction 90-16. Wshington, DC, U.S. Government Printing Office, 1973. 7. Deprtment of the Army, Surgeon Generl: Bttle Csulties nd Medicl Sttistics: U.S. Army Experience in the Koren Wr. Wshington, DC, U.S. Government Printing Office, 1973. 8. Ld J, Reister FA (editors): Medicl Sttistics in World Wr II. Wshington, DC, U.S. Government Printing Office, 1975. 9. Krlson BW, Herlitz J, Hrtford M, Hjlmrson A: Prognosis in men nd women coming to the emergency room with chest pin or other symptoms suggestive of cute myocrdil infrction. Coron Artery Dis 1993; 4: 761 7. 10. Wlker NJ, Sites FD, Shofer FS, Hollnder JE: Chrcteristics nd outcomes of young dults who present to the emergency deprtment with chest pin. Acd Emerg Med 2001; 8: 703 8. MILITARY MEDICINE, Vol. 173, Februry 2008 197