Cardiovascular Outcome After Surgery or Somatostatin Analogues
Condition: Acromegaly
MeSH terms: Acromegaly
Study type: Observational

Summary: 
      A direct comparison between the results of surgery or somatostatin analogues (SSA) on
      cardiovascular complication in acromegaly has never been performed.

      Our objective is to investigate whether first-line surgery or SSA have a different outcome on
      cardiomyopathy after 12 months. The design of the study is retrospective, comparative, non
      randomized, because of ethical problems.

      Setting University Hospital. All patients treated with SSA [either octreotide-LAR (10-40
      mg/q28d), or lanreotide (30-120 mg/q28d); dosages up-titrated to control GH and IGF-I levels]
      or operated on by transsphenoidal approach. For the purposes of this study only controlled
      patients will be included.

      Measurements Primary outcome measures were changes in left ventricular mass index (LVMi),
      diastolic [early to atrial mitral flow velocity (E/A)] and systolic perform-ance [LV ejection
      fraction (LVEF)]. Secondary outcome measures were reduction of total/HDL-cholesterol ratio,
      as a cardiovascular (CV) risk parameter, improvement of glucose profile and pituitary
      function, as indirect causes of CV improvement.

      Expected results: SSA and surgery groups should have similar results in terms of improvement
      of cardiomyopathy. However, recent data suggest that SSA reduce directly heart rate and
      cardiomyocytes performance: clinical implications of these evidences suggest that SSA will
      improve cardiovascular outcome more than surgery. Moreover, after surgery, replacement
      therapy already stabilised or of new onset, has never been considered so far in this setting.
    

Detailed description: 
      We will review all files from consecutive patients with active acromegaly coming to the Units
      of Endocrinology or Neurosurgery of the "Federico II" University of Naples from Jan 1st 1997
      to December 31st 2006, primarily treated with either surgery or depot SSA, i.e. lanreotide
      (LAN) or slow-release octreotide (LAR), and with an available follow-up of at least 12
      months. Due to the study design, this is a non randomized study. However, our routine
      procedure generally considers first-line treatment with SSA for 6-12 months, unless the
      tumors are clearly non invasive on Magnetic Resonance Imaging (MRI) and/or the patients who
      do not present any surgical or anesthesiological risk.

      Cure criteria are considered according with Giustina et al. Acromegaly is considered to be
      controlled if mean fasting GH levels were ≤2.5 μg/liter in presence of normal IGF-I levels
      for sex and age. Nadir GH after oral glucose load (oGTT) ≤1 μg/liter is also an option to
      evaluate disease control according with the 2000 Consensus Statement. However, oGTT is
      generally not routinely performed in patients receiving SSA, since GH-induced glucose
      suppression is likely to be mediated by the endogenous somatostatin tone. To avoid
      ascertainment bias, disease control after surgery and SSA will be only based on fasting GH
      and IGF-I levels. The diagnosis of acromegaly is defined as previously reported, by high
      serum GH levels during a 6 hr time course, not suppressible <1 µg/l after oGTT and high
      plasma IGF-I levels for age [expressed as value upper limit of normal range (ULN)].

      For the purpose of this study only the patients with controlled acromegaly will be included
      to provide a period of follow-up long enough to investigate changes in cardiomyopathy
      parameters.

      Study protocol: As for our routine procedure, at diagnosis all the patients undergo a
      complete metabolic and endocrine screening. After an overnight fasting, serum IGF-I levels
      are assayed twice in a single sample at the time 0 of the GH profile; GH levels are
      calculated as the mean value of at least 5 (up to 8) samples drawn every 30 min over a period
      of three-six hours and the average value will be considered for the statistical analysis;
      fasting total cholesterol, HDL cholesterol, glucose and insulin levels are also measured. The
      total/HDL-cholesterol ratio, index of cardiovascular risk, is calculated.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        We will review all files from consecutive patients with active acromegaly coming to the
        Units of Endocrinology or Neurosurgery of the "Federico II" University of Naples from Jan
        1st 1997 to December 31st 2006, primarily treated with either surgery or depot SSA, i.e.
        lanreotide (LAN) or slow-release octreotide (LAR), and with an available follow-up of at
        least 12 months. Due to the study design, this is a non ran-domized study. However, our
        routine procedure generally considers first-line treatment with SSA for 6-12 months, unless
        the tumors are clearly non invasive on Magnetic Resonance Imaging (MRI) and/or the patients
        who do not present any surgical or anesthesiological risk.
      
Biospecimen description: 
      Sera from most patients on a yearly bases are stored in our freezed at minus 80° for eventual
      further studies. No experimental parameters are included in the current study.
    
Keywords: Acromegaly; GH; IGF-I; Octreotide-LAR; Lanreotide; Transsphenoidal surgery