Fig. 6.1
Lung function test. FVC functional vital capacity, FEV1 forced expiratory volume in first second, PEF peak expiratory flow, NHANES III third national health and nutrition examination survey, l liters, s seconds
Fig. 6.2
ECG with left ventricular hypertrophy
A maximal exercise stress test was performed on a cycle ergometer (Fig. 6.3) starting with a workload of 50 watts (W) which was increased by 25 W every 2 minutes (min). The patient had to terminate the test due to exhaustion at 150 W. His heart rate at rest was 56/min and 152/min on exhaustion. Throughout the stress test and the recovery period, the patient was free of symptoms, and there were no signs of ischemia or arrhythmia on the ECG. The only pathologic finding was an increased blood pressure at peak exercise of 230/120 mmHg. Due to the elevated blood pressure and the positive Sokolow-Lyon Index, echocardiography (Fig. 6.4) was performed. A concentric left ventricular hypertrophy (end-diastolic diameter of the intraventricular septum [IVSd] in M-mode in the parasternal long axis view of 13 mm) and a mildly reduced left ventricular function with an ejection fraction of 49 % and hypokinesia of the anterior and anterolateral midventricular to apical segments were noted.
Fig. 6.3
Data of cycle ergometer. RPE rate of perceived exertion
Fig. 6.4
Left ventricular hypertrophy (LVH)
Blood tests (Fig. 6.5) showed a fasting plasma glucose of 6.6 mmol/L (119 mg/dL), HbA1c of 6.4 %, and dyslipidemia. Although treated with a statin, total cholesterol was 7.0 mmol/L (270 mg/dL), low-density lipoprotein (LDL) cholesterol was 4.0 mmol/L (155 mg/dL), high-density lipoprotein (HDL) cholesterol was 2.2 mmol/L (85 mg/dL), and triglycerides were 1.7 mmol/L (148 mg/dL).
Fig. 6.5
Blood parameters. hsCRP high-sensitivity C-reactive protein, HDL high-density lipoprotein, LDL low-density lipoprotein, CK-MB creatine kinase muscle-brain type, PTT partial thromboplastin time
Urine analysis (Fig. 6.6) showed microalbuminuria and glucosuria.
Fig. 6.6
Urinary analysis. Neg negative finding, kg kilogram, m meter, pH pondus hydrogenii, mg milligram, dl deciliter
6.2 Risk Stratification
In order to raise the patient’s awareness and understanding for essential and mandatory lifestyle changes, it is very useful to assess his risk for future vascular events. The following questions arise:
- 1.
Which variables do you need to predict the 10-year risk of heart attack and stroke according to HeartScore® in this patient?
Age, gender, smoking status, systolic blood pressure, total cholesterol, and country of residence [1] (see Fig. 6.7) are mandatory to calculate the 10-year risk for cardiovascular death according to HeartScore®. The inclusion of BMI into HeartScore® has been tested several times and BMI has been proven to be a very weak risk factor for CVD. As a result, the addition of BMI does not improve the predictive power of HeartScore® [1, 2]. According to the European Guidelines on CVD Prevention, patients with diabetes are considered at high risk and should therefore be treated with maximum intensity. Therefore, the inclusion of diabetes is not useful, since patients are being classified as high risk already.
- 2.
There are two models, high risk and low risk, which of them do you use?
Fig. 6.7
Score charts for high- and low-risk countries
The model has to be chosen according to the country of residence of the patient (see Table 6.1).
Table 6.1
Score charts for high and low risk countries
European low risk | Andorra, Austria, Belgium*, Cyprus, Denmark, Finland, France, Germany, Greece*, Iceland, Ireland, Israel, Italy, Luxembourg, Malta, Monaco, the Netherlands*, Norway, Portugal, San Marino, Slovenia, Spain*, Sweden*, Switzerland, and the United Kingdom |
European high risk | All other European countries |
Very high risk | Armenia, Azerbaijan, Belarus, Bulgaria, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Macedonia, FYR, Moldova, Russia, Ukraine, and Uzbekistan |
National versions are available for* | Belgium, Germany, Greece, the Netherlands, Spain, Sweden, and Poland |
For Austria, the low-risk model has to be chosen and calculates a 10-year risk of 5 % (age, 54 years; smoker; systolic blood pressure, 145 mmHg; total cholesterol, 7.0 mmol/L).
In our patient, risk estimation alone indicates an urgent need for preventive intervention to avoid a second cardiovascular event.
6.3 Diagnosis of Diabetes
Because of an elevated fasting plasma glucose level of 6.6 mmol/L (119 mg/dL), an elevated HbA1c of 6.4 % (46 mmol/mol), microalbuminuria, and glucosuria, it is mandatory to test for diabetes mellitus.
How do you efficiently and accurately diagnose diabetes in cardiac patients?
According to the most recent ESC Guidelines on diabetes, pre-diabetes, and cardiovascular diseases [2], it is recommended that the diagnosis of diabetes is based on HbA1c (if >6.5 % or > 48 mmol/mol) and fasting glucose (if >7.0 mmol/L or 126 mg/dL) combined or on an oral glucose tolerance test (OGTT, 2 h glucose > 11.1 mmol/L or >200 mg/dL) if still in doubt. (I, B) Since 2010, HbA1c may also be used to diagnose diabetes. Furthermore, HbA1c helps to assess the success of anti-glycemic therapy. HbA1c testing is highly specific compared with a 2 h OGTT or a fasting plasma glucose test. However, because HbA1c testing is not sensitive enough to rule out diabetes if levels are normal, the test should not be used for excluding diabetes [2]. Lower than expected levels of HbA1c can be seen in people with shortened red blood cell life span, as seen in glucose-6-phosphate dehydrogenase deficiency, sickle-cell disease, or any other condition causing premature red blood cell death. Conversely, higher than expected levels can be seen in people with a longer red blood cell life span, as in patients with vitamin B12 or folate deficiency. Elevated HbA1c levels represent poor glucose control. However, normal HbA1c levels still conform with a history of recent hypoglycemia or with spikes of hyperglycemia. Furthermore, HbA1c measures are not reliable, if the patient went on a diet or medical therapy within the last 6 weeks. In addition, patients with recent blood loss or hemolytic anemia are not suitable for this test [2].
Performing an OGTT is the method of choice to diagnose diabetes mellitus in this patient. Early stages of hyperglycemia and asymptomatic type 2 diabetes are best diagnosed by an OGTT (Fig. 6.8 [2] and 6.9) with an intake of 75 mg of glucose dissolved in 250–300 mL water within 5 min (body weight × 1.75 = mg of glucose for test; in this patient: 93.4 × 1.75 = 163.45 mg; but intake should not exceed 75 mg). In this patient the 2 h post-load glucose level was 12.2 mmol/L (220 mg/dL), which is diagnostic for diabetes (>11.1 mmol/L or 200 mg/dL). On a side note, his HbA1c was 6.4 % (48 mmol/mol) and fasting glucose was 6.6 mmol/L or 119 mg/dL, and consequently without an OGTT, the diagnosis of diabetes would have been missed.
Fig. 6.8
How to perform an oral glucose tolerance test
Fig. 6.9
Comparison of 2006 World Health Organization (WHO) and 2003/2011 and 2012 American Diabetes Association (ADA) diagnostic criteria for impaired fasting glucose, impaired glucose tolerance, and diabetes
Besides the diagnosis of diabetes, also impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) may be diagnosed using fasting glucose and OGTT.
An early diagnosis of diabetes is of utmost importance, since diabetes mellitus is associated with a more than twofold increase of cardiac mortality. Whereas patients with a previous myocardial infarction do have an increased risk of 4.0, the addition of the risk factor diabetes mellitus leads to a further increase, accumulating to 6.4 [2]. Figure 6.10 [2] presents a diagnostic algorithm of an efficient and practical diagnostic decision-making pathway for patients with diabetes mellitus (DM) or coronary artery disease (CAD). The presence of diabetes sets the patient at the highest possible risk regardless of other comorbidities. In a subsample of the Euro Heart Survey more than one-third of the patients with CAD who underwent an OGTT had an impaired glucose tolerance. Implementation of this simple, effective, and inexpensive test into clinical routine of patients with CAD would help diagnose diabetes mellitus and thus grant these high-risk patients access to an optimal medical, interventional, and surgical therapy [3].
Fig. 6.10
Algorithm for patients with coronary artery disease and diabetes mellitus. CAD coronary arterial disease, DM diabetes mellitus, HbA1C hemoglobin A1c, MI myocardial infarction, ECG electrocardiogram, ACS acute coronary syndrome, PFG plasma fasting glucose, IGT impaired glucose tolerance
Generally, metformin is recommended as the first-line therapy in newly diagnosed diabetes following evaluation of renal function. An estimated glomerular filtration rate (eGFR) of >50 ml/min is regarded as a cutoff value for metformin. If a target HbA1c of <7 % (53 mmol/mol) is not reached after a repeated measurement of HbA1c, the dosage of metformin may be increased up to 3000 mg, or, alternatively, a second agent may be added. In selected patients, such as our patient, a more stringent glucose control (HbA1c 6.0–6.5 % – 42–48 mmol/mol) might be considered if it can be achieved without hypoglycemia or other adverse events [2]. In concordance with the current guidelines, we started with metformin 500 mg 1-0-1 in our patient, as his eGFR is 74 mL/min.
6.4 Improving the Risk Factor Profile
The patient’s risk profile includes arterial hypertension, physical inactivity, smoking, obesity, dyslipidemia, and diabetes mellitus. Treatment goals for cardiovascular risk factors are depicted in Fig. 6.11.
