The acute myocardial infarction in very elderly

Archives of Gerontology and Geriatrics

30 (2000) 261–267

The acute myocardial infarction in very elderly

Giuseppe Aliberti *, Isabella Pulignano, Maria Proietta,Luigi Vincenzo De Michele, Salvatore Minisola

Dipartimento di Scienze Cliniche, Uni6ersita di Roma ‘La Sapienza’, Policlinico Umberto I,Viale del Policlinico, 00161 Rome, Italy

Received 18 November 1999; received in revised form 11 March 2000; accepted 13 March 2000

Abstract

A total 325 patients were studied at admission for myocardial infarction, measuringplasma fibrinogen (FBG), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH)and automatized hemocromocytometric parameters in order to contribute to explain theexcess mortality reported in very elderly patients. It was found that age positively correlatedwith fibrinogen and LDH values and inversely with CPK, hemoglobin concentration andlymphocyte count. The unpaired comparison of the variables studied in age subgroupsshowed no differences between patients aged 65 or less than 65 years and patients aged66–75 years. In patients aged over 75 years FBG, neutrophile count and LDH weresignificantly higher in respect to 65 or less and 66–75 years age subgroups and hemoglobinconcentration, red blood cell count, hematocrit and lymphocyte count were lower. In thevery elderly patients the study shows a biochemical feature suggesting delayed hospitalizationfor myocardial infarction, that may contribute to their poorer prognosis. © 2000 Publishedby Elsevier Science Ireland Ltd. All rights reserved.

Keywords: Very elderly; Myocardial infarction; Prognosis; Delayed admission

www.elsevier.com/locate/archger

1. Introduction

The role of age as an unfavorable prognostic factor for myocardial infarction hasbeen well established in several studies (Maggioni et al., 1993; Aguirre et al., 1994;Lee et al., 1995). The cause has been found in a higher incidence of multivesseldisease with aging (Tofler et al., 1988) or of previous silent or unrecognized

* Corresponding author. Tel.: +39-6-49970776; fax: +39-6-49970524.

0167-4943/00/$ - see front matter © 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.

PII: S 0 1 6 7 - 4 9 4 3 ( 0 0 ) 0 0 0 5 6 - X

G. Aliberti et al. / Arch. Gerontol. Geriatr. 30 (2000) 261–267262

myocardial infarction and in differences in treatment in older patients (Goldberg etal., 1989), in preexisting heart failure and decline in myocardial reserve (Wilcox andHampton, 1980; Appelgate et al., 1984) and in senile heart morphofunctionalmodifications (Olivetti et al., 1991; Wei, 1992). However, the explanation of thisrelationship still remains uncertain (Goldberg et al., 1989; Marcus et al., 1990). Asa matter of fact, no significant difference in the mortality rate between older andyounger groups of infarct patients has been found when the risk factors werecomparable, meaning that age itself is not an independent prognostic factor(Russek and Zohman, 1954). On the other hand, the difference in the mortalityratio of very elderly patients, 75 years age or older, reaching 30%, compared with10–15% of the other age classes (Latting and Silverman, 1980; GISSI, 1986;Goldberg et al., 1989) is very relevant.

The aim of the present study was to evaluate some laboratory parameters athospitalization for acute myocardial infarction in order to investigate if in the earlyphase differences might be found between the age subsets, contributing to explainthis excess mortality in very elderly patients.

2. Patients and methods

The study was carried out in 325 consecutive patients hospitalized for acutemyocardial infarction, 246 men and 79 women, 61.46911.00 and 70.03911.30years mean age, respectively. The criteria for inclusion in the study were thedevelopment of pathological Q-wave on ECG and the diagnostic changes ofcreatine phosphokinase (CPK) and lactate dehydrogenase (LDH) enzyme levels.Exclusion criteria were previous myocardial infarction or coronary surgery, im-paired liver or renal function, hematologic or coagulative disorders.

The following parameters were measured at the admission and before treatment:CPK, LDH plasmatic enzymes by routine methods (reference range for normaladults: 25–235, 100–400 U/l, respectively); automatized hemocromocytometricparameters by Technicon H™ device (Technicon Instr., Tarrytown, NY); fibrino-gen (FBG), chronometrically by addition of excess thrombin to dilute plasma froma standard curve of clotting times of known fibrinogen concentrations using a MLA1000 device (Baxter-Date Int., IL, USA; reference range for normal adults: 200–400 mg/dl).

The group of patients was divided into three subgroups: the first, consisting of188 patients aged 65 or less than 65 years, 161 men and 27 women with a mean ageof 54.9497.66 years and age range 29–65 years; the second, consisting of 85patients aged 66–75 years, 60 men and 25 women with a mean age of 69.8192.55years; the third, consisting of 52 patients aged over 75 years, 26 men and 26 womenwith a mean age of 80.8093.94 and age range 76–90 years.

The statistical analysis was performed with Statistica software (Statistica, 1993).For each variable the normality of distribution was tested with Shapiro–Wilk’s Wtest; in the group as a whole the multiple regression test was used for dependentvariable age; unpaired Student ‘t ’ test and x2 were used for variables comparisonbetween the subgroups.

G. Aliberti et al. / Arch. Gerontol. Geriatr. 30 (2000) 261–267 263

3. Results

The multiple regression correlations summary, shown in Table 1, showed in thegroup as a whole a significant positive correlation of age with FBG and LDH andan inverse correlation with lymphocyte count, hemoglobin concentration and CPK.

The unpaired comparison of variables between the subgroups, shown in Table 2,showed no differences between the patients aged 65 years or less and the patientsaged 66–75 years, while in the patients aged over 75 years FBG, neutrophile count,LDH were significantly higher in respect to both the subgroups of the patients aged65 years or less and 66–75 years and red blood cell count, hemoglobin concentra-tion, hematocrit and lymphocyte count were significantly lower.

The in-hospital case-fatality rate, shown in Table 3, was very higher in patientsaged over 75 years, while it was not significantly different in the subgroups ofpatients aged 65 years or less and 66–75 years.

4. Discussion

A total of 325 consecutive patients were studied at admission for acute myocar-dial infarction. According to the previous studies a significantly higher in-hospitalcase fatality ratio was found in the very elderly patients, aged over 75 years, whileit was almost similar in the subgroups of the patients aged 65 years or less and66–75 years. A first remark in this regard is that age was positively correlated withFBG and LDH and inversely with CPK levels, as assayed at hospitalization. Thisseems to indicate differences with aging in the biochemical pattern of myocardial

Table 1Multiple regression for dependent variable age in 325 patients in the early phase of myocardialinfarctiona

Independent variables P-levelb9S.E.Mean9S.D.

4189149 mg/dlFibrinogen 0.1690.05 0.00314.0091.8 g/dl −0.2390.12Hemoglobin 0.04

4.5290.57×106/mm3 −0.1290.09Red blood cells NSNS−0.1590.11Hematocrit 39.6595.47%NSPlatelets 250 629979 410/mm3 0.0690.05

White blood cells NS0.0590.1510 84894017/mm3

0.0590.15 NS811293642/mm3Neutrophils1029100/mm3 −0.0990.06Eosinophils NS

53949/mm3Basophils 0.0690.06 NSLymphocytes 17409838/mm3 −0.2090.06 0.001

−0.0190.05Monocytes NS6139267/mm3

CPK 113191188 U/l −0.2990.08 0.00029049752 U/l 0.1990.08LDH 0.02

a Regression summary: R=0.44; R2=0.20, P=0.000001. Relationships direction and magnitudeexpressed by b coefficients.


Table 2Comparison of variables (mean9S.D.) between infarct patient subgroups by agea

\7566–75B65Variables

408.469162.12 408.769147.14 475.909150.44b,°Fibrinogen (mg/dl)13.0092.06d,**13.9691.6214.0291.58Hemoglobin (g/dl)

4.5790.504.6490.49 4.2890.70d,*Red blood cells (×106/mmc)Hematocrit (%) 37.5096.36d,°°40.6594.95 40.2094.65

249 229986 508250 428969 848Platelets (/mmc) 250 734973 61611 57894815White blood cells (/mmc) 10 82194101 10 74993833

927494640a,°768393453Neutrophils (/mmc) 7909938631049215959166 63999Eosinophils (/mmc)

5791096094053935Basophils (/mmc)1733977118509949 14169712c,°Lymphocytes (/mmc)

Monocytes (/mmc) 5709309 64993016079311979987683591671CPK (U/L) 124891710

81498538869734 11159702a,°LDH (U/L)

a Values of P (B)565 vs.\75: =0.05;b =0.02;c =0.005;d =0.0001.° *66–75 vs.\75: =0.02;* =0.01;°° =0.005;** =0.001; 565 vs. 66–75=NS.

Table 3In-hospital case-fatality rates (CFR) in the infarct patients divided in subgroups by age and as a whole

CFR \75565 Total66–75

14/8524/188 20/52 58/325n38.46*,° 17.8416.4712.76%

* Chi-square p values: B0.0001 (\75 vs.565);°B0.01 (\75 vs. 66–75); 565 vs. 66–75=NS.

infarction presentation. Moreover, the unpaired comparison showed no differencesbetween the subgroups of the patients aged 65 years or less and 66–75 years in thevariables studied, as if for the biochemical aspects they belong to the samepopulation. In the very elderly patients, instead, a different feature was observed.Neutrophile count was significantly higher, meaning a more unfavorable clinicalfeature of the myocardial infarction in very elderly patients, since the prognosticvalue of this parameter as currently reported (Haines et al., 1983) and according tothe higher mortality ratio observed. Moreover, the lymphocyte count was signifi-cantly lower in the very elderly patients, rather as a sign of an increased steroidhormone stress secretion than, being inversely correlated with age in the groupconsidered as a whole, as an expression of an unascertained reduced lymphocyteproduction in the elderly (Sparrow et al., 1980).


A relevant contribution towards explaining this excess mortality in very elderlypatients seems to may be found considering the plasmatic enzyme and FBG values,showing significantly higher LDH and FBG levels in very elderly patients in respectto the two other age subgroups, while no such differences were found between theselatter. It is well known, in fact, that both LDH and FBG levels rise later after theonset of myocardial infarction (Eastham and Morgan, 1963; Cristal et al., 1983),while CPK levels decrease.

In this regard it seems noteworthy to report that in previous studies the CPKlevels, mainly investigated as markers of infarct size, were found lower in the agedin respect to younger infarct patients (Tofler et al., 1988; Goldberg et al., 1989;Smith et al., 1990) or showing no differences (Maggioni et al., 1993), while theLDH values were not considered.

The results, in accordance with these previous studies, showed in the early phaseof myocardial infarction, CPK levels not significantly different in the three sub-groups, although they were lower in the very elderly in respect to the subgroup of65 years of age or less infarct patients, while the LDH levels were significantlyhigher in the very elderly. This seems to suggest that hospitalization for myocardialinfarction of the very elderly patients was rather delayed in respect to the onset ofthe coronaric event. The fact also seems to be confirmed by the higher plasma FBGlevels, which are reported to increase later, in the first days after myocardialinfarction (Fulton and Duckett, 1976; Knudsen et al., 1979).

This seems to focus on the problem of the clinical presentation of myocardialinfarction in the very elderly, sometimes painless, extremely variable and unobtru-sive, as with general weakness, sudden vomiting, sweating or with a rapid deteriora-tion of the state of health for no apparent reason (Pathy, 1967). An acuteconfusional state or abrupt increase of mental disturbance, attributed to cerebralanoxia (Rodstein, 1956), is reported to possibly initiate the clinical feature and it iswell known that signs of stroke may overshadow an attending myocardial infarc-tion. In this regard the significantly lower hemoglobin concentration, red blood cellcount and hematocrit found in the very elderly patients, according to age relatedchanges in hemopoietic functions (Baldwin, 1988), may be relevant. Moreover, only19% of 387 elderly infarct patients have been reported to have a classical onset,with substernal or epigastric pain or discomfort (Pathy, 1967), while the BronxAging Group reported a 40% prevalence of silent, paucisyntomatic or atypicalmyocardial infarction presentation in patients aged 75 years or older (Nadelmannet al., 1990). Furthermore, they have been found to be unable sometimes to describetheir symptoms accurately or they do not remember their complaints (Yang et al.,1987).

In conclusion, this study shows that in the early phase of myocardial infarctiondifferences in biochemical parameters may be found in older patients in respect toyounger ones, mainly consisting of significantly higher LDH and FBG levels. Thisbiochemical pattern seems to prove delayed hospitalization in the older patientsthat may contribute to their poorer prognosis (Gurwitz et al., 1991), also suggestedby the significantly higher neutrophile count as well as by the lower lymphocytecount, mainly an expression of a worse stress condition. On the other hand, the


lower hemoglobin concentration, red cell count and hematocrit, found in the veryelderly, may unfavorably affect both the presentation and the evolution of myocar-dial infarction.

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The acute myocardial infarction in very elderly